It is still just calories in and calories out. Some people naturally have a higher metabolism and a higher basal metabolic rate. It still doesn’t change the equation.

Yes, it’s a well known fact that if you eat too few calories, that your metabolism slows down - and you burn less calories. That doesn’t make anything that the original poster said scientifically valid.

I saw all sorts of crazy crap that people believed would help them lose weight and tone when I was a part time fitness instructor like excercises that would help them spot reduce (no such thing) to people who tried to come into my classes wearing those plastic bags because they thought it would help them lose weight. They reported me to management plenty of times for not allowing them to come to my class like that and I would budge.

> It is still just calories in and calories out.

The problem with this line of thinking is the "just".

Sure, physics says it's calories in and out, and we all agree that mostly makes sense.

But -- how do you measure how many calories are going out? Sleep is known to have an impact on weight. How does one translate their sleep quality or sleep issues into a better "out" measure? How do you know how many calories are going out during all of the other things you do during the day? What about the thousands of assorted complex processes going on in your body that you aren't really aware of?

For the "in"... ok, so you studiously track everything you eat. What's the efficiency that your body absorbs all of the calories from the food you ate? How many of those calories pass through and aren't actually consumed? Is eating 1000 calories of lettuce really the same thing as eating 1000 calories of pork?

If fixing this for people was just about "the equation", weight loss would be a lot easier to solve.

"Calories in, calories out" is one of those things that sounds great, but is not nearly as practical for people to actually implement as people like to imagine.

Sleep only has a second order effect on weight. Almost all of the reasons that lack of sleep affect weight loss is due to overeating (calories in) and lack of exercise (calories in).

https://www.topfitnessmag.com/lifestyle/sleep-important-weig...

This is just like all of the studies showing diet soda causes weight gain.Diet soda doesn’t actually cause weight gain. Diet soda gives people the license to overeat and it may cause some people to crave real sugar more. I’m sure we’ve all seen people order a Double Quarter Pounder with Cheese, a large fry and a Diet Coke.

ah yes spot reduction, doing crunches will not remove the fat on your stomach. If anything it'll make your stomach bigger with muscle gains!

> Some people are naturally skinny and others put on weight quickly. This is already well known and shows that there are complex genetic inputs as well as other ones. We have to discover what those are. So saying it’s just calories in/out, stupid... nope!

I never really understood why this was always a catch-all trump card. So you can't gain/lose weight as easily as others. In my mind that just means you need to work harder rather than shrug your shoulders and say "nothing to be done". Specifically its people doing this that never look into their diet or are willing to change any of their habits.

Slightly related but Carol Dweck's growth mindset for education is literally this, but the difference is in people who believe they can't get in better shape and people that can.

Or people who are naturally fit with no effort vs. people who aren't willing to massively restrict their diet and live in discomfort for the rest of their lives since the body permanently adapts to expecting a certain amount of food: https://www.thecut.com/2016/05/weight-loss-metabolism-slows-...

First, I take issue with the cited article because the study referenced in the opening paragraph because they do not provide any discussion over limitations of their study. In particular, that members of the "Biggest Loser" show may have also been more extrinsically motivated by money and fame than intrinsically motivated to become healthy. Thus, when they failed to earn said money/fame, they returned to their normal behaviors.

> people who aren't willing to massively restrict their diet and live in discomfort for the rest of their lives

I also take issue with this statement. Many fitness motivation images on the Internet talk about rejecting temptation to work towards your goals. As I was thinking about this comment, I was reminded of Ben Stiller's pizza scene in the movie Dodgeball [1]. Jokes aside, the scene is a hyperbole to how even fit people are susceptible to temptation and take actions to not giving in. Not to Stiller's degree, but I can distinctly remember times where I just stare at the ice cream aisle with grocery shopping. It is my own mental discipline to not buy it. Quitting World of Warcraft to get in better shape is also a part of my past. Shifting to an active lifestyle is hard, it has a difficult initial start, but persevering through it has helped me become the healthier person I am. I also recall Jesse Shand's transformation [2], where I believe one of the phases of his weight loss was simply reducing the number of fast food meals he'd consume in a single sitting (instead of 8, only eat 7, etc).

[1] https://www.youtube.com/watch?v=PPmX2gNIqE8

[2] https://www.youtube.com/watch?v=jpy1FlGKYz0

There's a big difference willpowering yourself to stay at your natural state of skinnyness and willpowering through hunger-regulating systems in your body being permanently broken. Here's another reference if you didn't like the other study. https://www.latimes.com/science/sciencenow/la-sci-sn-weight-...

You still seem to confound skinniness and willpower and again, the second link I showed someone well into 40+ BMI changing. Secondly, this article has a few issues as well. The participants are older, which we know is difficult to lose weight at (which does support your claim, but not for the same reasons). The article also does not appear to compare the participant's appetite increases to those of "healthy" individuals. What does an "8" represent, and would any person show the same signs?

I will assume that formerly obese people have higher cravings. No doubt a former heroin addict has cravings. I will accept that it is harder for these individuals. But again, that does not mean you shrug your shoulders and say "that's the way it is".

I’ve never known anyone who was “naturally fit”, defining fitness as the ability to work out at a certain level of intensity for a given amount of time.

I’ve known people to be naturally skinny or even tone but not “fit”.

This still boils down to calories in/out though. Metabolism goes under the 'out' column. It fluctuates, sure, but it's just as much an 'out' variable as exercise is.

The body has a choice: burn the stuff now or lower metabolism and store the stuff for later. You can lower your intake, and the system can decide to lower metabolism to store some more. Obviously this can't go on forever, but maybe it can go on enough to impact other factors, like availability of glucose to run willpower.

Or not. Figuring out how and if those adjustments are made and how to control them is the next step after you say "calories in = calories out", which is only a first and smallest step in figuring it out.

It kind of is actually. Nobody escapes the law of universal conservation of energy. Sure some people due to genetics will store more of the energy they consume as fat than others. But if you have an energy deficit the body will consume itself to the tune of that exact deficit, period, end of. It will be a mixture of fat and muscle, but the body does try to maintain muscle to the extent you are utilizing it given there is sufficient protein to maintain it. So lift weights or do resistance training enough to keep the muscle you wish to retain and maintain a good amount of protein intake to support this as well, and the bulk of your body mass consumed will be fat. Other than that it is just maintaining an energy deficit, and the best technique is the one you personally can adhere to consistently.

> But metabolism has so many variables.

You're drastically overestimating the difference in people's metabolism.

> Some people are naturally skinny and others put on weight quickly.

This is about appetite. Skinny people have a smaller appetite than overweight people.

Show me a "skinny" person who can eat 4,000 calories a day and I'll show you a fat person.

This is a very false assumption, genetics absolutely do play a role in how much fat from dietary intake will be stored vs expelled as waste. Burning fat on the other hand, is universal and follows the law of conservation referred to in my other comment.

While I'm sure genetics makes a difference (as it does with everything), I doubt it's that significant. I'd be shocked if there's more than a 10% difference, if even that much.

Would love to see a source that backs up your claim.

It's enough of a difference to turn a surplus into even a deficit. Long term, it makes someone skinny or obese, or preferably normal weight.

Would love to see a source that backs up your claim.