If I had to choose between thermodynamics and medicine being wrong, and people not being able to accurately estimate how "much" they eat and how "little" they exercise, I'd bet all my money on the latter.
The simple reality is, people have vastly different appetites. I eat fast and am always hungry. I have two coworkers, one eats quite a bit less than me (often struggles to finish a standard portion), the other eats mich more but quite slowly.
3 different people, 3 vastly different eating habits. The reason people gain different amounts of weight most likely isn't in the differences between our bodies, but the differences between our minds.
Additionally, do you acknowledge that some drives are more irresistible than others? Can you hold your breath until you pass out?
Is it so hard to imagine these drives might differ from person to person? I fully acknowledge that, irrespective of your body's efficiency, if you could ignore your drive magically, you would lose weight with no problem, but that is far from a useful endpoint because the drive matters.
Ultimately it's still calories in vs out. But the out isn't just burning 500 calories running. It's what you burn doing your day to day too.
https://examine.com/faq/does-metabolism-vary-between-two-peo...
Metabolic rate does vary, and technically there could be large variance. However, statistically speaking it is unlikely the variance would apply to you. The majority of the population exists in a range of 200-300kcal from each other and do not possess hugely different metabolic rates.
Sure, if you're tracking your food intake closely, maintaining a significant deficit, and not losing weight, talk to a doctor about your thyroid. If you're putting in hours in the gym and eating a lot and not gaining any muscle, talk to your doctor about your testosterone level. But if you're looking to hormones and whatnot first, you're probably just deluding yourself.
There is. Read the "physiology" chapter at https://en.wikipedia.org/wiki/Adipose_tissue
TLDR: Blood sugar spikes above certain level are toxic, so the body responds with an emergency action of stashing the sugar wherever possible, including muscle, liver, and fat tissue. The former two are rather limited in their capacity, while the latter is unlimited. At the "hardware" level, that's all there is to obesity.
At the higher levels there are other emerging phenomena:
- This process is prone to overshooting the sugar egress, creating a "sugar crash", which has to lead to another sugar binge. This becomes an unhealthy see-saw. Note that the fat cells are consuming sugar but they can't release it back, they can only release fatty acids, hence sugar deficit must be replenished through food.
- The see-saw may end up messing the appetite and the balance of hormones that partake in regulating the metabolism. This yields the so-called "metabolic syndrome" with all its co-morbid factors: https://en.wikipedia.org/wiki/Metabolic_syndrome
- The hormonal imbalance changes the person's appetite, creating a vicious cycle.
Simple sugars are addictive. Just try going without to see how bad it can get - keep eating the fats, the meats, the complex carbs, just cut out the sugars, starches, and flours.
This is another problem that people can and have solved. You simply aren't eating as much as you think, so you take meticulous track of your caloric intake, and once you realize you eat a lot less than you thought, force yourself to eat X 100s of calories over normal intake per day. This is likely a quantity of food that causes physical discomfort initially, but it works.
Ignoring issues like Crohn's, "I can't gain weight" is just as much an excuse as "I can't lose weight", although perhaps more socially accepted due to body type voodoo.
I disagree that qualifies as an elephant. Some of those people could have some sort of known genetic defect that makes them unable to properly digest food. Some of them do not eat as much as you think that they eat. For instance, I had plenty of snacks yesterday at a neighbor's house. They were 1 peanut and two pieces of a jerky-like thing the size of my fingernail. Without that additional information, you would have thought that I ate far more.
I'm now almost 40 years old and have never been overweight a day in my life. Over the past 20 years my weight has always stayed within about a 15 pound range no matter how much/little I ate and/or exercised.
I participated in a caloric intake study at one point in time and I had a higher caloric intake than anyone in the study group. I was not trying to eat more; it was just that until I hit my mid 20s I had to consume excessive quantities of food just to keep from losing weight.
Yes, healthy people gain weight on 5,000 calorie per day diets. No, they don't develop all the metabolic and psychological maladies described in the documentary.
Why is it that some people, regardless of how much they eat and how little they exercise, never put on weight? That, to me, is the elephant in the room.
What is going on in these peoples bodies that is kept out of popular science with regard to weight loss? We know that thyroid hormone function affects weight and metabolism. In women reproductive hormones also affect weight, oestrogen is a hormone present in both males and females, so there's some crossover there. We know that adrenal function can affect weight. We know that insulin resistance can affect weight.
There has to be more to it that calories in - calories out = weigh gain or loss.
If you have an unaddressed thyroid, reproductive hormone, insulin, or adrenal issue you're going to be working hard to address your weight.
It is my suspicion that fixing the diet first improves weight control better than exercise because food is medicine. Anything you put in your body on a daily basis can be medicinal in that it can act to help your body restore homoeostasis or move further away from it.