[ericd]

I eat as much as I want and don’t exercise enough, why am I far from obese? I’m currently scarfing down tortilla chips and guacamole.

To me, that suggests that maybe that simplistic (and frequently repeated) mental model is inaccurate or insufficient in some way.

My working theory is that most Americans’ gut microbiome is massively screwed up due to some combination of genetic, dietary, and environmental factors, and it changes what they crave, and how their body reacts to the food they eat. But I’m very much a layman on this topic.

[idle_zealot]

Of course not 100% of people are obese. Individual susceptibility varies, and as you mention could well be influenced by how the environment or common diets impacts the body, and further by how those changes in the body impact the mind. That said, its not really surprising that a decent portion of the population crave food rich in starches, fat, refined sugar, and salt. On an evolutionary timescale these nutrients have been scarse, so desiring them was advantageous. At the same time, problems from overconsumption were likely vanishingly rare, so there was no pressure to develope countermeasures like decreases appetite in responce to long-term abundance. In many ways our bodies and minds are not adapted for modern life, and this is a distinct problem from our inadvertent mass-poisoning ourselves.

[nradov]

Stating that you eat as much as you want is meaningless. How many kcal/day is that exactly? Most people are terrible at estimating their calorie intake.

[ericd]

No idea, don’t care to know. I drink a huge amount of whole milk, eat lots of cheese, dark chocolate, etc, etc, so I’m sure it’s not a small number of calories. The point was that I’m eating as much as I want, and not restraining myself at all, so it’s not a matter of willpower or anything like that. I don’t have to fight cravings to stay thin, and I’m not a spring chicken with a super fast metabolism, so there’s clearly some other difference.

People putting it down to eating less are parroting the food equivalent of abstinence-based sex education, and we’ve been drumming on that for like the last 30 years. We have to find what’s making people want to eat to excess, not just tell people to eat less and exercise more. That obviously doesn’t work.

[nradov]

I'm putting it down to eating less. Regardless of what you think you're eating the reality is that your metabolism and digestion (gut microbiome or whatever) is nothing special. If you actually measure and weigh everything you consume, you'll find the total calories are in the normal range for someone your size.

If you think that there's something else going on, then let's see some hard data.

[DoingSomeThings]

CICO is the mechanical answer. The question OP is getting at is "why" they naturally eat less. The poster is saying "I eat until I'm full and don't gain weight". For other people, they eat until they're full and gain weight.

Personally, my "satiated" level is very low. When trying to gain weight while weightlifting, it was difficult to eat the amount of calories needed. I know others who can easily eat twice as much as me in a sitting and not feel full. Something different in happening in our bodies to signal "stop".

[ericd]

Exactly, thanks for explaining it.

[seabird]

People want to eat to excess because they're psychologically/emotionally rewarded for doing so, because eating whatever and whenever you could was pretty fucking important for tens of thousands of years before we had infinite McDonald's and microwave dinners.

Eating less and exercising more does work. Talk to dedicated lifters about their cutting/bulking, where they want to be, and talk to them about it again in six months if you want to see how effective it is. It doesn't work for a lot of people because in the short, medium, and arguably even long term, it doesn't make you feel good.

There are a handful of people that can struggle to gain or lose weight on a diet appropriate for the amount of exercise they do. You may be one of them. If you are one of those people, asking why other people struggle with it is like being a 6'6" basketball player and wondering why somebody who is 5'9" struggles to dunk like you can.

[ericd]

Yep, of course you lose weight if you starve yourself. But why do so many people seem to have a natural eating “setpoint” that fattens them, and others don’t? My guess is that it’s largely the types of foods they’re eating. Not fatty ones, which have been vilified (like I said, my food mix includes a lot of whole milk, cheese, and other very fatty food), but ones that mess with their digestion and satiety signals. For example, if you drink sweet drinks, they make you hungrier. I’m pretty sure if I eat more McDonald’s and microwave dinners rather than the simple foods I generally eat, I’ll fatten right up, and I’ll join in the ranks of those that crave more food than needed.

[seabird]

>Yep, of course you lose weight if you starve yourself

There is a massive difference between being at a calorie deficit and starving yourself. I don't even know what to say -- this horse has been beaten to death by countless thousands of people and it's wild that anecdotal evidence with a sample size of you is enough to justify theorizing an alternative to an incredibly simple idea that until a few generations ago, there was absolutely no evolutionary pressure to not want to eat everything you can.

[ericd]

Sorry for the hyperbole. I think you're being a bit uncharitable, though, I'm of course not basing this entirely on myself. Lots of people I know have a bar for being satiated that maintains weight without effort. But many clearly do not. Is it obvious why some do, and some don't? It's clearly not down to willpower.

I suppose you'd say that some areas experienced more evolutionary pressure to eat as much as possible than others due to differences in food security?

But being hungry/unsatiated is distracting and can decrease your performance on every other task you do, so I don't really agree that there's no counterpressure. And I doubt that people in even those less food secure regions are just hungry all the time, like some obese people here describe being. It really seems like something just gets messed up in the signalling, which makes it seem more like a health problem/malfunction than some built-in evolutionary drive that doesn't fit the modern world.