The HIIT part of their training has a different purpose than the slower part. Each type of training serves a different purpose.
A lot of discussion currently also revolves around putting more emphasis on "Zone 2 training" with many hours & kms trained at lower intensity, for better endurance and efficiency of slow-twitch fibers.
> read interviews with e.g. professional cyclists, they train significantly less, but at much higher intensities than 7 years ago
Do you have any reference for this claim?
Jay implied this was a change throughout the peloton, but you can still see old school strategies doing well (Bernal for example does huge volume in base from strava).
It has come to the point that tweaking nutrition science to feed athletes better so they can train more is a key aspect of the ultra endurance training (e.g. the Norwegian Iron Men around Olaf Alexander Bu).
Studies have found that humans cannot consume more calories than 2.5x their basal metabolic rate.
https://www.science.org/doi/10.1126/sciadv.aaw0341
And nobody is saying you can't expend more energy for shorter times. It is just that you can't sustain it over long times because of our metabolic limits.
>> Someone on the internet wrote "humans cannot consume more calories than 2.5x their basal metabolic rate" -- which study might they be quoting?
> I am not aware of a specific study that states that humans cannot consume more calories than 2.5x their basal metabolic rate. Basal metabolic rate (BMR) is the amount of energy a person needs to maintain basic bodily functions such as breathing and digestion, and it can vary greatly depending on factors such as age, sex, and muscle mass. However, the total daily calorie needs of an individual also depend on their level of physical activity and other lifestyle factors. So, it's likely that this statement is a generalization or an over simplification.
"Incorporating data from overfeeding studies, we find evidence for an alimentary energy supply limit in humans of ~2.5× BMR"
A good book the topic is Herman Ponzer's "Burn"
The main issue seems the surface area of the GI tract.
https://openheart.bmj.com/content/9/2/e002154
> Conclusion: Although older male endurance athletes experienced an increased risk of AF, the long-term risk of stroke was substantially reduced compared with non-athletes.
Higher probability with zero exercise, lowest probability at moderate exercise, but an increase in probability as you enter the extreme territory. In my case, 1000+ hours/year for 8 years led to this outcome
Eliud Kipchoge, WR in marathon, seems to only be doing one hard faster than race pace workout each week. Call that the HIT. The others are slow or race pace. What actually stands out most to me is the specificity of running close to a race pace marathon every week. https://www.sweatelite.co/eliud-kipchoge-a-typical-week-of-t...
Then on the other end of the spectrum, the Ingebrigsten family of runners seems to put an emphasis on quality. But even though they do more faster running they keep a lid on the intensity to avoid training to exhaustion. It actually reminds me more of the "Grease the Groove" concept where the faster running may be more for neurological reasons. https://www.outsideonline.com/health/running/culture-running...
Anyway, neither of these two training models seem to have much in common with HIT. The bulk of the workouts are easy intensity and they are both seemingly ware of the dangers of high intensity. That's where injuries come from and so there can't be too much of it.
Suspect that this is also for neurological reasons
Certainly not the same effect. HIT training doesn’t improve respiratory or cardiovascular fitness as effectively as continuous training does, and it doesn’t condition the muscles for endurance as effectively as continuous training does either.
I don’t know much about cycling, but I know a lot about endurance running, and the typical training regime will utilise continuous training (such as long runs, recovery runs…), as well as high intensity training and some training that’s a mixture of both, like fartleks. The reason being they all produce different results, and you want the benefit of all of them.
Here’s a video made by Eliud Kipchoge‘s athletics team that talks about the benefit of long runs:
They have other videos about the other training intensities they use as well. Their training facility is also at a rather high altitude, which is basically its own form of training as well, or a legal form of blood doping, depending on how you look at it.
He is hands down the best of all time and is totally in a league of his own. He trains constantly. His entire life revolves around it.
Assuming you're not looking to become an endurance athlete, is conditioning muscles for endurance something one should aim for? Why?
"Improved cardiometabolic health" sounds like something everyone - including us sedentary workers with families and not much free time - might benefit from. Being able to achieve health improvements in short training sessions would appear to be a really important option.
Furthermore a more proper fitness regime will fix your posture and improve your quality of life immensely. Things like a flight of stairs, getting in and out of the car, carrying a couple bags of groceries, or just getting up from the floor will become much easier. Again, not going into hours of training, but to 15-30 minutes a few times per week. Your kids can watch. :)
I don't challenge the research results. Just saying that there are more upsides than just cardiometabolic health, as someone who has seen this first-hand, going from couch potato to a little more active lifestyle.
Is it the most time efficient way to fix posture? For sue not, but it should work.
People that can't be bothered to even walk are not going to stick to intense workouts. It is completely delusional.
Not to mention, we know these do not train the same energy systems or have the same benefits too.
This whole discussion is dumb.
Is there any science here, or just anecdata from elite athletes, who are often terrible judges of their talent? It's really hard to judge this stuff.
That is not to say that HIT doesn't work, and doing something is certainly better than doing nothing in any case, but if you want to maximise the training effect w.r.t. endurance for a given time budget, doing mostly LIT is the better option.
(Sorry, I have to ask) but results in what?
It sounds like there's a risk of focussing on (endurance) athletes, not on unfit sedentary desk workers. Talking about which of the former benefits most from which particular training methodology could be missing the point, which is that it's the latter who are the group who really need to get off our backsides to improve our general health.
In other words, getting a few extra % of performance out of already fit people is of interest to a minority, but is irrelevant as far as public health policy is concerned.
This is actually incorrect. It's not well known, but the science is actually very clear about this. HIIT is much more effective then long term continuous exercise for VO2 max. This has been shown across Several studies.
Many coaches and training programs don't incorporate the science into their training regimes. So so called "experts" don't really know. You'll be surprised how ingrained the belief is and it's hard to turn it around if you've been under the belief for years that you need to do long continuous training routines to improve cardio.
Roger Bannister the first person to clear the 4 minute mile used HIIT exclusively for his training and he's the first person to change the science around this. The myth, however, persists and you still see people plugging in miles and miles into their training routine when HIIT works better.
HIIT doesn't "work better" than continuous training in this respect, it simply targets a different part of the system than continuous training does. For instance if you wanted to increase the stroke volume of your heart (a component of VO2 max), then the scientifically proven best way to do that is with extended aerobic exercise (continuous training).
VO2 max is also not the only measure of fitness. For example, lactate threshold is an incredibly important factor for distance running, and it is improved by extended periods of training at your lactate threshold (continuous training). Incidentally, you wouldn't be excepted to reach your lactate threshold during a 1 mile run. For even more context, Eliud Kipchoge doesn't have an especially remarkable VO2 max, it's about what you'd expect from any elite athlete. But he does have an absolutely insane lactate threshold.
Modern endurance training is incredibly science based. That's why if you go and look for a marathon training plan on the internet, even the most basic ones are going to include a mixture of different training intensities, distances and durations. It's also why the athletics team who made that video I posted also have other videos describing the high intensity components of their training regime, and why the members of this athletics team have succeeded in pushing the limits endurance performance much further than they ever have been pushed before.
If you'd like to take up debunking training myths, I'd suggest you look a little bit further into what VO2 max actually is, and what other types of fitness metrics also exist.
It depends on the level you're looking at. Lower level components compose to form higher level components. For example heart efficiency is one component that composes with others to form VO2 max. Muscle lifting strength is not a a component that makes up for this. Of course I am looking at a higher level metric then you suggest. There's no point in arguing how granular things are. I could turn it around and talk about how the mitochondria and DNA is a component of stroke volume but that's just, again, pointless.
>HIIT doesn't "work better" than continuous training in this respect, it simply targets a different part of the system than continuous training does. For instance if you wanted to increase the stroke volume of your heart (a component of VO2 max), then the scientifically proven best way to do that is with extended aerobic exercise (continuous training).
You are incorrect about stroke volume. Recent studies show that cardiovascular and muscular adaptations to HIIT are comparable and sometimes even greater than those of steady-state training. In regards to cardiovascular adaptations, these studies show that HIIT increases stroke volume and VO2max to a greater degree than steady-state cardio (stroke volume: 10% greater improvement; VO2max: 6% greater improvement). These studies also suggest HIIT increases mitochondrial density, which allows us to create more energy, to a similar degree as steady-state but in less time and fewer days per week.
Sources: https://www.researchgate.net/publication/308600869_High-Inte...
The above paper shows how VO2 max is increased by HIIT
https://www.unm.edu/~lkravitz/Article%20folder/HIITvsCardio....
The above page shows how VO2 max compared with Continuous training is the same if not better.
https://runningmagazine.ca/the-scene/the-surprisingly-simple...
The above is a page on Roger Bannisters training routine. He exclusively did intervals and ran only 5 hours per week to achieve the first 4 minute mile, thereby proving that the most popular and almost exclusive training routine for the time (continuous training) was not as effective as HIIT.
Nowadays athlete runners regularly blow past the 4 minute limit because interval training is now common place. In fact people in the know... people who train the top athletes know that intervals are the primary training routine to improve VO2 max (and virtually all associated lower level components that influence it, if you want to be pedantic.) So this "myth" I'm "debunking" is mostly a myth among the more amateur athletes (aka people who don't break 4 minute miles). I believe you are likely part of this peer group which is a logical deduction given your incorrect reasoning.
If you'd like to debunk other people I suggest you cite resources because you are mistaken on this area and if you read the science you would know. Spitting out a lot of technical jargon while making you sound intelligent does not take the place of actual the science and cited sources that serve to prove a point. Thank you.
Like other commentors have said, certainly not the same effects, only maybe for the effects tested. High intensity training for example has a much higher risk of injury.
Maybe, maybe not. But running isn't the only method of cardiovascular exercise.
I've asked on HN a couple times in the past for citations that support this meme and haven't yet found a good source on this. The connection between caloric restriction and weight loss isn't as straight forward as people seem to think, despite that being the standard correlation pushed since the 1950s.
Calories seems to be the catchall metric pushed around, but it seems to be as much about what you eat, not just eating less. Although I'm sure asking someone to simply "eat less" would still ultimately contribute to weight loss. Whether calories is the thing that matters is the question.
Weight loss is complicated because of the added dimension of satiety. If I eat proteins, vegetables and fats without counting I'll be around my baseline. But with sugar and carbs it's impossible to not overshoot without being terribly hungry. Also with less insulin sensitivity found in obese/pre-diabetics people, ingested food can not be efficiently used and end up stored, leading to the vicious cycle of being tired and still hungry.
Calories are measured by burning them, so that means we are using two different measurements that may overlap but are not compatible.
In the Calories model would it be possible to explain why people with diabetics type 1, that don't use insulin stay thin even though they would eat massive amounts?
It's easy to explain your example with diabetics: very simply insulin is what allow muscle to use glucose, but also what stop the body from using its fat reserves. From your link:
> Desperate to stop its cells from starving, her body had released hormones that, in turn, released byproducts called ketones that turned her blood acidic. If she had not been rushed to the emergency room, she would have died.
This is similar to the effect of a ketogenic diet, when you avoid eating carbs to avoid insulin secretion. Diabetics type 1 don't produce insulin, so they just skip insulin shoots to stay in that "mode" but it has obviously other serious health side-effects for them as discussed in that article.
I never said individuals were the same and converted calories with the same efficiency. Hence why there is a lot of variation in TDEE. But once you have figured the TDEE for an individual, calorie counting becomes very accurate. Just from the fitness community there is an overwhelming body of research and evidence: https://sci-fit.net/bulking-deficit-gaining/. If you are in calorie deficit, you lose weight. If you are in a surplus, you gain.
If you will eat once a week, you will dispose of calories you did not absorbed. And you will be starwing by the end of the week, making you passive, weak and tired.
Continuing on your point the body is there not a closed system as defined as:
> In a closed system, no mass may be transferred in or out of the system boundaries. The system always contains the same amount of matter, but (sensible) heat and (boundary) work can be exchanged across the boundary of the system. Whether a system can exchange heat, work, or both is dependent on the property of its boundary. [1]
[0]https://en.wikipedia.org/wiki/Refeeding_syndrome [1]https://en.wikipedia.org/wiki/Closed_system
Since your stating that eating once a day is the same as eating once a day. Would you have any sources for that claim?
Did you know there is allot of research going into the effects of intermittent fasting[0]?
If you would search for OMAD (one meal a day) on google or reddit you would see that that statement does not hold. There are many changes because blood sugar will stay stable during the day. Nor will there be insulin spikes. There are health startups starting just for stable glucose levels and the health benefits by using continuous glucose monitors[1].
They already attracted many from the health and longevity communities. It's also possible not to use their product by just eating once a day.
[0]https://www.hopkinsmedicine.org/health/wellness-and-preventi... [1]https://www.levelshealth.com/
To my knowledge this doesn't break the CICO model. The disease (e.g. type 1 diabetes) reduces or eliminates production of insulin which triggers metabolism of glucose. Since you're metabolizing less (or no) glucose, you're not gaining as much energy and passing most all that out through waste.
If you have a disease you need to consider that your energy expenditure isn't inherently going to be the same as studies estimating from healthy individuals. This doesn't break the model, it just means your intake and expenditure are different than most healthy individuals. People with hypothyroidism have similar issues. Is the CICO model great for these people? If you account for such factors the underlying principles should hold true.
[0]https://www.healthline.com/health/diabetes/insulin-effects-o...
I wouldn't call those rules “extra”. After all, we're talking about human metabolism and what is digestible or not is central. The calories we're talking about under this topic has nothing to do with steam engines, except that both steam engines and humans take some input, called calories.
I don't see any conundrum with type 1 diabetes. They might have a different metabolism that counts differently which calories are in.
By the way, do you have a reference for this claim of yours [0]:
> people without insulin are able to stay thin, while eating massive amounts of calories
At that moment CICO dies, because you won't be able to measure anything and just have black box which you give whatever number makes sense in the end.
Not that it matters because the cells in human body use ATP not calories. As such calories are at best a proxy for how much food.
But that is issue with CICO, it's like magic box and we only have to count IN, as much at what makes the calculation correct later on, also with OUT. That is not very scientific. Because we are unable to reproduce anything.
I have posted the article before, have you read it? https://www.everydayhealth.com/eating-disorders/diabulimia/
"Calories" are simply a unit of energy. The energy released by the utilization of ATP can be measured in any unit of measure you like for energy. It won't change the fact that the unit can be calories.
This is like arguing about Celsius vs some other unit.
Likewise, the CICO model has been replicated over and over again in high quality studies that don't rely on self-reported intake. And this model and information are used by thousands of people every year to manipulate their bodyweight and composition at will in sports like bodybuilding or ones with weight classes.
Indeed, treating the body as a black box makes this even easier as tracking caloric intake and your bodyweight is sufficient to do this and apps like Macrofactor do all the math for you.
You are under the incorrect understanding that human body is closed system. Food doesn't need to be digested and what is digested doesn't need to be stored in fat cells.
Question if you would eat all the food once a week would it have the same effect? Because in a closed system it would, you can fuel the car little by little each day or fill the whole tank. But after one week of fasting they body will respond much different, a person can even die of even trying that scenario [1]
Did anyone lose 5 kilo by switching to a light product?
But the issue at hand was why people without insulin can eat massive amounts of food but won't gain any weight? Can't explain that with CICO, you can with other models[2].
> "Calories" are simply a unit of energy. The energy released by the utilization of ATP can be measured in any unit of measure you like for energy. It won't change the fact that the unit can be calories.
This statement is not correct, Calories is burning food. While metabolism goes through absolutely complex system. Kerb cycle, where glucose, ketones, fatty-acids and oxygen are turned in ATP, Link is only 1 small part and doesn't even cover how food was digested before that, by the gut biom, stomach acids. [3]
Human metabolism is too complex to discuss here in the comments.
[0]https://www.health.harvard.edu/staying-healthy/stop-counting...
[1]https://en.wikipedia.org/wiki/Refeeding_syndrome
You have no idea what you're talking about.
This is textbook level stuff and you clearly haven't read a single one. Your wiki level understanding is missing the forest for the chlorophyll.
You aren't entitled to another person's time and effort when you've decided your googling is in any way comparable to literal years of study in environments where you actually get feedback on your understanding.
There is no reason for those Ad hominem attacks.
I explained to you that you have fundamental misunderstandings so vast in scope that it would take several hours to explain them to you. This criticism was rooted in years of education and research that can't be compressed into a single comment.
If you google things to confirm your worldview, you will get the evidence you wish.
If you wish to see how those who successfully manipulate their body composition at will down to the pound, you would look to those populations who do so like bodybuilders and strength athletes and those who compete in weight classes.
And if you wished to have the ability to discern when an argument is irrelevant or outright wrong, to understand the most basic elements of physiology and physics and chemistry, you would put in the time to read the textbooks which are explicitly designed to convey this information to you in a comprehensive way designed for understanding rather than relying on university PR pieces.
> But that is issue with CICO, it's like magic box and we only have to count IN, as much at what makes the calculation correct later on, also with OUT. That is not very scientific.
The whole physics is a magic box. We find qualities of materials after we measure them, because that's how the model is constructed.
Let's say that I have a model called mass in volume out (MIVO). It states that mass of a liquid predicts its volume. We measure how much volume a certain amount of water takes, vary the amount, see if the model works, and it does. But a MIVO-denier is not happy, because our measurements with water doesn't reproduce with mercury. Well, duh, because they have different densities. MIVO-denier is still not satisfied, because now they have to go through the tedious task of finding the density of the material they have to work with before being able to apply the model. Furthermore, they have to keep the temperature constant, not mix liquids, etc. Yet, MIVO works regardless of how difficult it is to quantify, measure, or use.
PS: Thanks for the reference. I had missed it.
Here is a link from Harvard saying to stop counting calories[0]. Here is another link from Havard[1] going over the contestants of the biggest loser and how they are doing now.
There is new model The Carbohydrate-Insulin Model of Obesity[2] which has explanation that does explain the edge cases CICO is missing.
But calories are measuring food, and at the moment there is no better way to have overview of how much across different types of food. But CICO itself doesn't help with long term weight loss.
[0]https://www.health.harvard.edu/staying-healthy/stop-counting...
[1]https://www.health.harvard.edu/diet-and-weight-loss/lessons-...
I don't see how these references show that. They are irrelevant to our discussion. The first Harvard piece is bullshit, written for those feel-good types who don't want to put in the effort of losing weight. The second one has nothing to do with “calories in, calories out”. It just states some observation on contestants. The paper has “calories in, calories out” in the title, yet doesn't talk about the model at all. It talks about something else, called conventional model.
Nowhere in “calories in, calories out” I understand that it is easy to create deficit by eating junk food or that one can go back to their old lifestyle once they have lost weight. People fight with an imaginary enemy.
I think that I've explained my view as well as I could. Thanks for your participation.
>how do we know there aren't factors yet to be discovered?
We don't and can't (by definition), that's part of the scientific process. Part of that process requires us to find evidence to the contrary or provide a viable testable competing argument. We don't just waive our hands in the air and claim magic gremlins are making people skinny or fat since there are likely limits to human understanding and knowledge, especially at any given specific point on time.
Most the evidence out there, that I'm aware of, vehemently supports the CICO model and it makes sense as a complex system resting up very well studied chemical and physical phenomena. The only thing broken seems to be a general understanding of the model being discussed.
https://www.health.harvard.edu/diet-and-weight-loss/lessons-...
What has changed is that without insulin glucose will stay in their blood damaging organs and veins.
Insulin signals to cells take up glucose and other nutrients, first organs like the liver, then the muscles.
More information in the link from healthline. https://www.healthline.com/health/diabetes/insulin-effects-o...
If a diabetic is consuming many calories but also excreting many calories, that is still calories in and calories out.
That’s not necessarily true for diabetics, so someone with that condition will have a different experience with it.
> Despite intensive research, the causes of the obesity epidemic remain incompletely understood and conventional calorie-restricted diets continue to lack long-term efficacy.
If CICO does not factor in what is not stored or digested. Therefor it's a flawed model. Therefor it would be better to look at what is working, and wath was working before we got unto the low fat craze. In the 1950 up to 1980 bodybuilders where eating low carb high protein diets. Everyone was thin back then, just now we are returning to knowlegde.
But the thing is according to latest science obesity the focus is not on CICO anymore. Would be great if more people would be willing to conduct their own N=1 studies and try low carb dieet, keto, or intermittent fasting. It works the same way by keeping insulin low. It might do wonders.
[0]https://www.healthline.com/nutrition/what-are-obesogens
[1]https://www.health.harvard.edu/staying-healthy/stop-counting...
Twice I have been on very extreme calorie counting regimens for months at a time combined with substantial weight lifting and cardio.
Both times I have observed that if I reduce calories the first thing that happens is I start to feel colder in the same environments. My body adjusts to my new caloric intake by reducing my metabolic rate it seems.
I learned about the idea of a “set point” fifteen years ago and I believe it’s related to what I’ve observed.
I have friends who can do something as simple as cutting out a morning cappuccino and they lose weight as a result. If I do that, there is no measurable difference unless I cut much deeper and substantially increase activity at the same time. Then the weight comes off for a bit and then plateaus again, sometimes for weeks or until I make another adjustment.
One of the times I went through this weight loss regiment I had an air displacement plethysmograph near the end of the weight loss that concluded I had 178lbs lean body mass. I had likely bulked up a little through all the weightlifting I was doing but have always had a fair bit of muscle so you might expect my resting calorie burn to be very stable and for small adjustments in calories to not impact resting metabolic rate, but that’s not what I observed in practice.
If you want to lose weight, just keep eating increasingly less calories.
Because that trivializes the problem. There’s physiological pushback on many dimensions.
The responses should have been of the form, “Absolutely but this is very hard for some people for the following reasons…”. That changes to one part of the equation can have unintended consequences that change the other part.
>The problem is that CICO as the law of energy conservation is NOT a model of obesity. It's conflated with the straw-man "Conventional Model" described by Ludwig: independent, unregulated intake and expenditure implying that getting fat and treating obesity are all about willpower
Personally though, I find it rather easy to maintain a particular weight. I just wear pants with the right waist size and if they feel tight I take it easy on eating for a day or two. I have had the same weight +/- 1.5kg for 20 years. Losing weight beyond my comfortable baseline is exceedingly difficult though.
I'm supposedly on a 1500 calorie deficit, eating ~1300-1500 calories a day and burning ~3000, according to my fitbit. But I'm only losing about 0.5lbs per week.
My conclusion is that I'm really only burning 2000 calories despite HIIT 3x/week, strength training 4x/week, and cardio 6x/week. If it weren't for all this training I would likely be gaining weight on what would otherwise be a reduced calorie diet for someone my size per every major TDEE calculation
I'm not so sure about that, I see a lot of claims otherwise on this article's thread which blows my mind a bit.
It's definitely an issue calculating and managing the calories out portion and for some people, it may not be an effective model to manage weight with diet and exercise, but I'm reading a lot of "this model is wrong" which is a little baffling to me.
Is it possible the caloric measurements are off? Absolutely, we may not even be considering all metabolic pathways, but hopefully a lot of its getting covered. CICO should be used as anchor points to help you guide your diet and find what works for you because everyone is a little different. Don't like a lot of vegetables, coffee make you sleepy and lazy? Hate cardio but love weight lifting or vice versa?
Try something else, but CICO can help you make a better grounded basis of comparison here to find what mixture works best for your body to manage weight and get or keep the body composition you desire. Does the model simply not work for your lifestyle? Try something else! But is it wrong? Eh, I don't think so.
Also body composition changes can make “weight loss” difficult as you replace fat with muscle. You can also get a gross estimate of muscle/water/fat mass to see those changes (or go get a very accurate measurement a few times in a facility equipped for such things).
Online TDEE calculators almost always overestimate expenditure, as do smartwatches. On the intake side, people lie to themselves constantly. First, they generally don't actually weigh their portions. In the rare event they really are weighing their food, they'll "accidentally" load up 4.3oz of something, then input it into their tracker as 4oz. Then they'll neglect to log their sauces and condiments, because it's "only" 20kcal for a tablespoon. These discrepancies add up.
Invariably, these ridiculous claims come down to people being liars, not just to others, but to themselves.
Losses were at like 5-10% the rate they "should have" been. Totally worthless.
Meanwhile weight lifting has always worked for me a large multiple as well as it "should", for weight loss, if you go by calculators that try to figure how many calories an activity burns.
I reckon that in both cases those two approaches must be having large (and opposite) effects on my resting metabolic rate.
I don't mean to imply that you won't burn a lot of calories cycling, quite the opposite, I think it is one of the easiest and gentlest ways to do so. You are however overstating what most non-elite cyclists can regularly accomplish in terms of calorie burn per hour.
Source: I have averaged 450hrs/yr for last 3 years and closely monitor my data.
Regardless of whether calories are completely indigestible or totally digestible the above still holds.
The issue is: How are we defining calories IN?
Consider the extreme example of having a parasitic worm living in your digestive system. Is IN == [food passing mouth] or is IN == [food not being ingested by worm(s)]?
Now consider "normal" digestive flora. How are we defining IN here?
I was hinting at something bigger than just a nitpick. I'm hypothesizing that gut flora interfere with macronutrient ingestion in a statistically significant way.
Microorganisms exist which produce glucose from materials that, if ingested by a human, would be emitted as waste.
What if colonies of these microorganisms were present in the human gut and unevenly distributed in the population?
CICO is a great approach for the general population, and works great even amongst professionals that have weight management as their career (bodybuilders).
1. Having a hole in your gas tank (parasite(s) e.g. a tapeworm)
2. Having a modification to your fuel tank to convert ethanol into octane (non-parasitic digestive microorganisms a.k.a. "gut flora")
Gut biome bacteria consumed an amount of those calories. How many? It varies from person to person.
So calories in = calories out, but we don't know how many were used by the person, how many by the gut flora, and how many were excreted do to inability to metabolize. Ergo, hardly basic physics.
Reductionism is only useful if you know how to apply it.
If this wasn't the case, you'd have discovered a solution to famine.
And gastric bypasses are one of the most effective interventions available for people with such disorderd eating that lifestyle changes can't stick.
It is an objective fact that caloric surpluses and deficits are fundamental to manipulating bodyweight.
Any solution will be about getting people to maintain a surplus or deficit long enough to reach their goal weight.
There are many ways to communicate that to people, but pretending or trying to convince others that it isn't true is factually incorrect and literally counter-productive to their goals.
But it's ok. I loose weight by exercising and eating less. Like the climate change denialists, you can lead people down the dark path if you like.
Me I'll stick with me 3kg loss of weight every month and celebrate.
It's missing the forest for the chlorophyll.
No one eats the exact same thing everyday.
And you can eat less or more throughout the year.
You've never had a holiday feast?
People who maintain the same weight simply eat their maintenance calories on average over the long term.
That's just how averages work.
I feel like you have some kinda fundamental misunderstanding of something to not understand this, but I don't know what it could be.
You are also correct - caloric deficit is not very sustainable long term for a large number of people.
There is ongoing study to figure out why — for example, why some people are much less able to stick to a diet, or have constant food cravings, and so on. That’s not at odds with what you’re questioning. The focus is on those areas because the requirement of a caloric deficit for weight loss is one of the most reliable observations we have so far.
That's nothing compared to what some people had to deal with e.g. surviving famines. That takes some serious mental fortitude, but I would imagine after that experience you'd be perfectly fine if dinner was served late. If you ever read Siddartha, there's this part where the protagonist learned how to fast with the Samanas in the forest, and not everyone knows how to deal with that sensation and accept it as just another sensation in life.
On the other hand, I know people who get into this bizarre state if they are hungry, not long after whatever their normal mealtime might be sometimes. People joke around about being "hangry" but its a real thing for some people. I can see how if you haven't learned how to accept the sensation of hunger, and all you know with that feeling of hunger through your life is to immediately satiate that sensation, sticking to a caloric deficit would not be easy.
https://www.publish.csiro.au/RD/RD20326
The CSIRO has been researching for decades as to what the best bang for buck is with regards exercise.
> people pushing the idea that diet / food restriction alone is sufficient for weight loss
Diet/food restriction alone is strictly sufficient for weight loss: I'm pretty sure this is uncontroversially true, but it sounds like you're saying it isn't. Am I misunderstanding you?
In the isolated context of losing weight, it doesn't seem like exercise is essential. Or to state in less absolute terms, exercise has less influence than diet choices for purposes of losing weight and maintaining it.
In my case, I noticed that the pounds melted off when I stopped drinking sugary sodas and eating bread/snacks and switched to more vegetables with olive oil. When I started exercising regularly, I actually gained more weight.
The thing that messes up the simplistic idea of "exercise burns calories so with 2nd law of thermodynamics you lose weight" ... is the body's overwhelming desire to maintain homeostasis. (https://www.google.com/search?q=homeostasis)
Homeostasis means that more exercise can cause more hunger and thus bigger meals which offsets the exercise so no weight is lost.
Likewise, deliberately eating less causes the body to conserve energy and do less physical activity which re-balances the body to not lose any weight.
For many folks, a long-term way to adjust the homeostasis is to change the diet from high-carb to low-carb and switch out the 400-calorie Starbucks frappuccinos and sugary sodas to green tea and 0-calorie sparkling water. These diet alterations have more chances of success than maintaining the discipline of burning 500+ calories a week via exercise.
Exercise is essential for healthy heart and bone strength but there are contradictory factors when used as a tool to specifically lose weight.
My hypothesis is that the equation that weight loss is related to calorie intake minus expenditure, but I think the conclusions one draws from it fail to take into account how much the body can control expenditure.
My body seems to naturally drift up in fat weight, very slowly -- probably around a pound per year -- no matter how much I eat. If I cut calories a lot, I can lose fat. After that, my fat level drifts back up to the old target weight pretty quickly, and then up slowly again. I'm pretty sure if I plotted my fat from the time I became an adult, it would be a pretty straight line, with short-term dips and recoveries for diets.
Losing weight sustainably would mean resetting that target somehow. I don't know how. Changing my diet and exercise levels don't seem to do much for fat levels (but do more for my general fitness and health).
Daily metrics can vary wildly without affecting overall result.
My solution, and mine alone after trying oh so many different diets and strategies, went through regular aerobic exercise, at a rate of 3-4 hours per week. In my case it was swimming, because I like it; cycling or running would have had the same effect, I believe.
It worked. I lost almost 30kg over about 2.5 years. Why did it work? I don't really know. I can tell you that basal expenditure certainly has gone up, as I had to get into shape to swim 4-5km a week. Of course, swimming a few km introduces some expenditure of its own. However, I had already tried gym and other sports, which should have the same effects, with far worse weight control outcomes.
So, for me, regular aerobic sessions of longer than 45min did the trick. I don't know why, so I can't promise it will work for anyone else, but you might as well try it for a few months. Don't expect huge, rapid, losses in weight, just a very consistent downward trend.
At current trajectory I'll be at normal weight by summer. Two years ago and for many years before I was balancing on the edge between overweight and obese.
I *still* had to really starve myself to lose fat. My aerobic fitness was excellent, as was my flexibility. My core strength was awesome. Fat was another matter.
I'm not the only one like that.
I know people for whom cutting down eating works, and people for whom exercise works. I'm not one of them.
As a footnote, I couldn't lose 30kg without seriously injuring myself. I'm overweight, but not deeply obese. Losing 15-20kg would put me at an ideal fat level.
Yes, this is has been observed and studied. From this page: https://physiqonomics.com/constrained-energy-model/ the relavent source materials are:
https://pubmed.ncbi.nlm.nih.gov/26832439/ https://pubmed.ncbi.nlm.nih.gov/34453886/ https://pubmed.ncbi.nlm.nih.gov/34519717/
So, yes, it seems that the body "compensates" and controls expendeture as you've suggested.
Speaking in general, there are a lot of details to consider for CICO. When people count calories to below their TDEE, their estimate of TDEE is just that, an estimate, not their actual TDEE.
When calories are counted, how accurate are calories being counted? FDA regulations in the US call for the nutritional information on packaging to be +/- 20%, and when audited, the information is often found to be outside that ranges.
Every gram of glycogen stored in your muscles, the body also stores 4 grams of water. The cycle of exercise, fasting, caloric restriction, and refeeding and glycogen storage are going to cause large swings in weight that can make it hard to pull out trends until several weeks/months have gone by, but frequently people are micro-focused on daily weight flucuations and draw their conclusions about diet and weightloss from what is effectively changes in glycogen storage/water weight.
While the thermodynamics aren't assailable, it turns out that the calorie system is in fact quite fallable and bad!
There's a lot of good material on why, I like this talk: https://www.youtube.com/watch?v=aJQxadvsmEQ
But simply put:
- Our system for measuring how much "calorie" is in any given food is extremely problematic and unrelated to how the body captures energy
- Our system for estimating how much "calorie" a human body uses is extremely problematic and error-ridden.
- Our systemized ignorance towards the relationship in the body between energy storage and energy consumption, as well as all the factors influencing this system. The same advice or strategy simply doesn't work the same way for two people. But our advice and labels can't capture that.
As we engineers know "garbage in, garbage out". Well, when all of the data in this system is garbage, it's no surprise that the function outputs garbage.
Currently the calorie count at least gives me an upper bound, and at least it's on the box and applies no matter who looks at it. How would you do better?
A better system? Not quite sure, but as always: criticism of current failures does not, by rule, have to come paired with suggestions for improvement.
Arguing that calories in doesn't matter is nearly on the level of Holocaust denialism, as the main picture evidence there is of the effects of calorie deficits.
Measuring food through calories, which are derived from burning food is therefor quite old technology, it's from 1800 when steam engines where main way of powering the western world.
As a thought example to push CICO model to it's end: For example we can't eat coal, but it's very calorie dense. According to CICO model we should be able to eat just little bit of coal, and drink tiny amount of fuel. So that would also suggest there is more to the story of nutrition then CICO.
Mammals are not as simple as factory machines.
For example CICO would suggest to lose weight to eat 500 calories less then normal, as average that would be 2500 for men. But if we would rephrase that: In order to lose weight eat 1/5 less then normal. Then that would have the same effect, that is issue with calories they tell a story about food but it's not the full story. [0]https://en.wikipedia.org/wiki/Citric_acid_cycle
Food (calories in) is just a form of energy your body is capable of utilizing. Fat is just a physical medium to store energy for use in your body. For your body to move and perform actions (live), you require energy. All things considered at this scale, if you expend more energy than you consume, you'll ultimately either die (due to lack of energy) or use other forms of energy in your body (e.g. fat).
This is of course the 30,000 ft view and there's a lot of complex biology and chemistry going on but it's pretty straightforward if you believe the law of conservation of energy is correct and our bodies aren't doing some sort of nuclear physics to process energy and instead relying on various forms of chemical and physical energy.
As you point out, it's not so cut and dry though in practice. There's a time component here and our bodies get quite clever. We build up efficiency of certain tasks over time requiring less energy usage. We resist building muscle because it requires more energy to maintain. Some food's energy density isn't perceived very well by our bodies and we remain more or less hungry irrelevant of potential calories making it more difficult to maintain a calorie deficit/diet based solely on our bodies senses. Many nutritional information products don't accurately measure calories of food, sometimes making it difficult to use as a base metric (theres a lot of errors in these measurements, especially by small food producers/providers). We also have incredible difficulty trying to estimate how many calories our body is actually expending because it's a fairly complex system (the "calories out" part of the equation) although there are some figures out there to help you estimate these within some general ranges depending on factors like age, diet, fitness, activity and so on--it's not perfect but it's something to work with quantitatively.
The benefit of calorie counting though is that there are fairly basic physical and chemical principles at play that make it a useful tool in weight loss and management. Even if a bit variable (both the in and out) and sometimes inaccurately represented, it gives us something fairly quantitative to work with, measure, and change around to control our weight. We can measure it and change other variables in our lifestyles to, over time, manage weight. It works and the statement is valid but it's not simple to use by any means, there's a lot one needs to learn over time to better learn how to measure their in/out and overall body feeling based on these factors.
Your body temperature goes up and down, changing how much energy is spent by body. Your ability to perform goes up and down - you become sleepy and tired, your brain spends less energy and that is that (yes it has impact on your attention and performance). You cant stop it from happening. You may try to exercise the same and can easily become unable to.
Your body gets rid of calories in poo and piss, when sweating or not.
Your body can just turn off functions and generally malfunctions and you dont have direct control over it.
If we looked at total energy of your gasoline we'd need to consider mass to energy conversion as well... but your body can't do that either. Energy your body can metabolize is clearly a subset of total energy available. It's certainly an estimate and it's not perfect but it's useful.
This looks like a digestible introductory guide: https://themedicalbiochemistrypage.org/digestion-and-digesti...
And a brief description of how all that helps inform calorie counts on nutrition labels: https://en.m.wikipedia.org/wiki/Atwater_system
People make entire career studying these sort of processes. Over time the information is refined. All of this ultimately helps inform how we measure and quantify things like calorie counts on food labels. Again, not perfect, but the process works and improves over time. It's a complex macroscopic system relative to the underlying chemistry and physics but if we assume larger systems are built on, composed, and governed by principles of constituent systems then we have a way of slowly understanding these complex processes and using that knowledge to our advantage.
Just as with software systems we rely on abstract processes below us to talk about things. That doesn't mean the high level abstractions are ignoring the details, it's just that there's value in talking about things simplistically like "calories in" and "calories out" without people looking to take very literal interpretations and trying to convert total energy possible into kcals. Heck, this is why they're "Calories" and not "calories" and why "Cal" has even been proposed to help avoid this sort of confusion.
The assumption that body resembles simple closed physical model is absurd.
You might just die before you loose all that weight. Moreover, you have high chance to develop long term health issues.
If the issue is lack of some specific vitamins or minerals you may correct it before you die without starting to eat again.
External factors certainly come into play like environment. You're not a completely closed system as you point out based solely on food. You may sit in a cold office shivering throughout the day or in a hot room sweating, these factors will effect your energy expenditure (and even intake) differently just to maintain your existence.
Something similar will happen with excess ethanol consumption. Your body will preferentially use ethanol for immediate energy needs, but there is no pathway to store it as fat. However any fat or carbohydrates in the diet will immediately undergo lipogenesis while the ethanol is metabolized.
The end result is that it’s physiologically impossible to gain body fat on a diet of lean protein and wine or spirits. However that’s a rather unhealthy diet otherwise so I wouldn’t recommend going all in on the piss out the protein plan.
It’s good to know though that if you’re taking an alcohol cheat day then stay away from beer and mixed drinks as well as fat and carbs all day and until the next morning. Instead eat something like lean chicken or fish with near zero calorie vegetables like lettuce or cucumbers or what have you.
I think the understanding about dietary calories comes from the agricultural world where calories are much more involved in the economics of animal growth and weight gain. So we might not even be that sure that what we consider dietary calories are accurate for humans.
Assuming they are accurate, each individual digests a different % of all calories they ingest and it depends on many factors. It's a very imprecise science.
If you want, you can eat a given number of calories each day of just one meal (like Huel or Soylent) for a month. Then, for the last week of the month, you can see how much weight you gained or lost over 7 days. You will also need a medic to estimate your basal metabolic rate and you would need to stick to your daily physical activity habits consistently. And then you can arrive at some number of what % of dietary calories you absorbed for that particular food with those particular eating times, exercise habits, and so on.
I think it's a very impractical test. Maybe it might be easier to do in a very controlled environment in terms of energy expenditure, like in weightlessness. But then the weightlessness is a factor in digestion, too.
If someone found a way to accurately determine what % of dietary or fuel calories humans really absorb, the data would probably be as impactful in our understanding of diets as the Minnesota starvation experiment.
Then your actual rate, whatever it is or how much it varies, hardly matters long term. Sure there would be variance, but on the whole, long term, you are only caring about the weight on the scale. So you measure calories in and your weight, and given you are consistent about burning calories exercising and the food choices in your diet, dialing back calories in will make a change on the scale, maybe a bigger or smaller one for different people, but a change no less. No one runs on air.
If you worry about macros (eg. hitting your proteins) you can get even better results by building muscle (which increases your metabolism and make you burn more fat) and avoiding a bunch of health issues likely linked to eating modern processed crap.
That said, the phrase: > without making your calorie intake less than your expenditure you will not loose weight
is correct and not a meme. It's just that your expenditure is hard to track and can be influenced by a lot of factors.
What I found that works wonders is to: - 1. keep your diet and fitness regimen as constant as possible, no matter what it is - 2. swap food with lower calories and higher protein intake, while trying to avoid processed food - 3. increase exercise without adding food - 4. measure your weight every morning at the same time - 5. do that until you stop gaining weight and your weight is constant for a few weeks - 6. reduce calories by doing step 2 or 3 again until you start losing a bit of weight - 7. keep doing it until you hit your target weight
I did this to lose weight years ago and it worked well. The main advantage is you don't have to worry about counting calories.
Last year instead I just went carnivore (admittedly, I did it to sort out other health issues, the weight loss was a welcome side benefit) and I found myself feeling full (thanks to the higher fat intake) and eating a sensible amount of meat, which helped me lose 10kgs over ~10 weeks. I'm sure not eating carbs (ketosis) also played a role.
I have a hard time believing this. Here is the first link from googling "cico weight loss studies":
https://legionathletics.com/cico-diet/
it's only a "meme" to those that have been convinced by people who are trying to sell you a specific diet/lifestyle (most commonly fasting or low carb)
This is not a "meme", it is almost universally accepted science by nutrition scientists at this point. This includes both theoretical reasons, as well as actual, legit studies with human subjects.
> Calories seems to be the catchall metric pushed around, but it seems to be as much about what you eat, not just eating less.
Not sure what you mean by "it" when you say "it seems to be as much about what you eat."
> Whether calories is the thing that matters is the question.
Matters for what?
If you mean in the strict sense that you are able to control someone's total food intake, then yes, you can induce any amount of weight loss you want by limiting their caloric intake.
If you mean "matters" in terms of getting real people in the real world to actually lose weight? That's a much more complicated question, because the number one variable that controls the amount and duration of weight loss is how long you stick with the diet.
Any "diet" that causes a caloric deficit will cause weight loss. Some do this by directly counting calories and targeting a lower number. Some do this by causing you to eat foods that make you fuller, thereby making you limit the amount of calories without thinking about it. You can even take medication that just cause you to not be hungry, which is the most effective in some sense.
The thing is, most diets are hard to stick to, or at least most people don't stick to diets. I personally counted calories as I found it the "easiest" in some sense (though I also had to learn a lot about how to eat in a more satiating way so not to be hungry.) I used that to lose a lot of weight. I've now regained a lot of that weight, partly planned (as part of a bulk), partly unplanned (I got injured so stopped training, and then decided to focus less on weight control and eat more, knowing that I would gain weight in an unplanned fashion.)
I think I finally figured out why I hate CICO so much: it's usually presented in a motte-and-bailey style. It's used to dismiss more-complex advice or observations and presented as if it's all you need to look at to model weight loss and gain to a useful level, then when it's pointed out that the terms are so vague, hard to actually measure, and don't address the effects of feedback loops on metabolism, that it's like trying to model the behavior of aircraft with gravity but without lift, and therefore damn near useless, the fallback is "well it's still technically true, blah blah blah". Sure, it's technically true, it's just... not very useful on its own, and constantly bringing it up as if it's all that matters is grating.
There are drugs that say otherwise. As a side effect of medication, I've had to increase my calorie intake to maintain my weight.
Not to mention the relative bio-availability of foods differs even when their calories don't. Fats and Proteins need more processing per calorie than Carbohydrates.
I'm also fairly certain there are limits to the human bodies ability to absorb calories. i.e. you could saturate your diet by eating way too many calories, but your eventual weight gain would be at the limit of your body's ability to store fat.
Is it a medication that increases energy expenditure? Something that boosts your metabolism?
For a very specific set of effects.
Other effects vary widely person to person.
I'm much more familiar with the evidence on strength training, where it seems that volume and intensity both have important roles. But at this point in my life, I no longer have the time to train as often as I'd like!
https://www.outsideonline.com/health/training-performance/po...
> With particularly high rates of knee and ankle sprains and strains, neuromuscular training and pre-strengthening programs, which have been previously demonstrated to be effective among young athletes, may be particularly worthwhile in prospective participants
Some people find success in organizing their life to get enough exercise in the natural way, as part of activities of their day, but I think the popularity of HIIT in recent days clearly indicates there's also lots of people who want to optimize for minimum of time spent on exercising. Myself I'm one of such people.
The real question is if you can get more done in the time available to you with HIIT or LISS cardio.
If you're sufficiently time constrained, HIIT will win.
But past a certain threshhold, LISS will always allow you to perform a greater volume of work with lower recovery costs and lower injury risks and, consequentially, greater benefits to health and fitness.
For overall health, going for "failure" in weight lifting appears to be the delusional to me; it's much better to lift at a consistent, repeatable level than to greatly increase the risk of injury chasing short term gains. When injured, your volume is going to be zero.
It's a good tidbit for "something is better than nothing", but no more than that.
Maybe not 500lbs but somebody could certainly eventually deadlift 400lbs from 3x8 minutes once a week, as long as they keep it intense and keep increasing the weight. I say that as someone who can deadlift more than 400lbs after many years of practicing around 30 minutes/week. If you're lifting hard, a week is barely enough time for the body to recover anyway.
I believe you, but you are really confusing people who don't know what it takes like the poster above.
"I feel that is roughly equivalent to dead lifting 500 lbs."
It is and it's not. No one naturally deadlifts 500lbs. Maybe 315, maybe. 500lbs is 3+ years of training. Most won't ever hit it even after 10. (Diet, sleep, injuries). A lot of 10 year olds can run 6min miles due to low bw though. It's two completely different standards.
With that said, you are absolute underrating the difficulty of both.
I’ve never believed this — only because my weight is so consistent and my eating is not. My body must have a way to regulate the absorption of calories from the gut. When I have some insanely high calorie meal, my body doesn’t necessarily absorb all the calories. This seems easy to measure, so I must be wrong. Or…
“ Ultraprocessed foods — such as refined starchy snacks, cereals, crackers, energy bars, baked goods, sodas and sweets — can be particularly harmful for weight gain, as they are rapidly digested and flood the bloodstream with glucose, fructose and amino acids, which are converted to fat by the liver.”
The real “myth” of calories in = calories out is that it’s possible to do it by feel. It takes a lot of work and math, like spreadsheet-level, to actually track calories in and out. So even though it is physically true as a concept, it’s not a good weight management strategy for most people.
Sugary snacks don’t make you feel very full for their caloric content. So unless you’re literally writing down the caloric information on the wrapper and comparing it to your total daily activity, it’s easy to overeat.
The real myth is that you can track calories in and calories out.
How do you measure how many calories your body absorbs from the food you eat?
How do you measure your calories out, particularly your resting metabolic rate?
Here's a hint -- the body changes its resting metabolic rate in response to calories in! Probably! Unless you eat junk food, and then maybe it doesn't!
In practise you don't need to track the out because it doesn't change much per day. It's not easy to burn 200 calories but it's easy to consume them. That's why it's common to hear that weight loss happens in the kitchen.
It does require work to understand your particular body, and discipline to do it consistently. Which is again, why it is not a good technique for most people. Most people don’t have the time, motivation, or really the need to do what this woman (in the video) is doing.
Apps like Macrofactor do it for you. You just track what you eat and your weight.
One secret about using CICO is that you do not need to know the gut absorption rate! You just need to track the calories before absorption, the numbers printed on the box. Easy these days with a smartphone app. The measurement does not need to be perfect at all. It only has to be decent on average. You can have variable accuracy of 25% on any given food and still get well under 10% on average for a week. It doesn’t matter if there’s a bias either, if you track your weight. The reason absorption and bias don’t matter is because you’re doing science with a black-box (your body). Measure the known input, monitor the output. Do it for a long time and you’ll find the maintenance input. Track input above that and verify mass gain, track below and verify loss. The maintenance value you come up with will “absorb” and bias, and gut calorie conversion rate, and other inaccuracies.
Measuring output is easy with a heart rate monitor. Changing metabolism we already discussed, but important to know that the range of elasticity is like around 15%, and in practice for any give person may be lower. It’s not some massive factor you can’t predict, it’s within a narrow enough range for the majority of people, statistically, that you don’t need to worry too much. And it will be accounted for if you track calories and weight over a long enough time frame.
And here is a recent peer-reviewed article that summarizes the debate: Ludwig, D. S., Apovian, C. M., Aronne, L. J., Astrup, A., Cantley, L. C., Ebbeling, C. B., ... & Friedman, M. I. (2022). Competing paradigms of obesity pathogenesis: energy balance versus carbohydrate-insulin models. European journal of clinical nutrition, 76(9), 1209-1221.
Regardless of diet you will lose weight if you eat fewer calories than your body is burning. It will be harder if you eat junk food, but quite possible.
To add to what someone else said, you probably ate below your threshold to be able to maintain your weight. You can't guess this, the only way to get an accurate ESTIMATE on how much you actually ate in calories is to measure. Even pros over/under estimate what they eat in terms of calories
That's only one side of the equation.
It is a basically proven fact (and largely implied by physics) that `calorie intake - expenditure = net weight change`. That is pretty much beyond dispute.
It is also true that some things affect expenditure, and it seems likely that most people have a "set point" that your body attempts to return to. This is also almost certainly changeable, as people have managed to change it in the past. (And this is less surely true than other things known.)
So yes, it's entirely possible to eat "inconsistently" and not have net weight change, your body is probably subconciously causing you to eat less after you eat large meals, and vice versa. Or possibly causing you to expend more energy after large meals.
People locked in a box will not be able to cheat and will demonstrate this.
No, our digestive tracts are extremely good at extracting any and all usable calories from our food.
100% of the time, when someone makes this claim, they are mis-estimating either their intake or expenditure, or not tracking for a long enough time period to escape the error bars inherent in daily hydration variance.
What's harder to refute is the loss of weight due to calorie restriction which is mostly physics. This is what the gp is talking about.
Also, weight gain/loss should be measured on a weekly scale rather than daily. You might feel like your eating isn't consistent but it could be on a weekly-basis. For example, you might barely eat one day but eat 3500 calories the next. That seems like inconsistent dieting but in actuality, they average each other out.
Just consider how much flatulence varies meal-to-meal, that's largely produced by calories guests living in your gut "burned" instead of you.
The trouble is it's a complex ecosystem hosting many lives, controlled by hormonal knobs affecting behavior/activity-level and energy storage, and the makeup of the food hugely affects how much is absorbed and at what rate.
Everyone knows first-hand when over-eating a massive meal of hard to digest foods there's a substantial amount of energy deposited in the toilet... And wild pigs / pet dogs don't get excited about eating human feces for lack of caloric value.
It's just an upper bound, nothing more.
Show me 1 conventionally conceived of "endurance athlete" amateur mid of the pack or professional who has adapted this? Marathon, Iron man etc. Just 1. I'd love to see if anyone got a result in a marathon etc that was like a pb or close to a pb this way. I highly doubt.
you could with tapeworms!
However, your point about body mass is correct, without making your calorie intake less than your expenditure you will not loose weight. I also recall that there have been some studies that found it might be harder with HIT, because you are hungrier after HIT than low intensity exercise.