Let’s say I am carrying 20 extra lbs on my caboose. 3500 cal x 20 = 70,000 calories that my body has at its disposal to run on when I run out of (food) fuel in the bloodstream. Right?
So…with ALL THOSE CALORIES at its disposal, enough for at least a month, WHY do I get hungry? Shouldn’t we have evolved not to feel any hunger at all until all of our stored surplus fuel (i.e. FAT) is gone? It seems so incredibly stupid that your body would still prompt you to eat when there is no physical need for more calories. Especially since excess weight is ostensibly so dangerous and life-threatening. What, is your body stupid?
Fat does not equal protein, minerals, vitamins, etc…
And evolution is not a process toward perfection, just a process toward giving birth to the next generation. If something is not detrimental to survival, it isn’t likely to disappear. Hunger is more useful than no hunger, so it isn’t likely to be going away any time soon.
The reason is simply that it’s only recently that stable, secure supplies of food are available at any time. Prior to that, it was advantageous to store excess food as fat and maintain a hunger reflex to ensure sufficient energy reserves existed for times when they wouldn’t.
No, your body isn’t stupid. If you only ate when all your reserves were exhausted you would always be just one meal from starvation. Now THAT would be extremely stupid and a sure recipe for almost immediate extinction of any life form that practiced it.
Under natural conditions, the supply of food is always irregular. You need to keep a reserve on hand in order to cope with the shortages of food that happen frequently.
Our problem is that we evolved under such conditions but now have an essentially unlimited supply of food (at least in developed countries). We end up stocking reserves of fat for a shortage that never comes (unless we create one by restricting our intake).
What Grey just said. We haven’t had time to evolve to adapt to the modern food situation. Even with time it may not matter if fat asses don’t affect our reproductive success.
A few (or even a lot of) extra pounds generally doesn’t kill you until after you’ve raised your baby hominids to an age where they can cope on their own; you’ll just live to 65 instead of 75. That being the case, evolution favored hominids who gave themselves the largest possible margin of safety against starvation by eating whenever their stomach wasn’t full, no matter how big they got.
If extra pounds tended to kill you will your kids were too young to take care of themselves, then perhaps evolution might have favored hominids with a more sophisticated hunger drive, i.e. one that does indeed say “stop eating, fatass, you’ve had enough.”
Try only eating what you can run down and kill … I think you’ll find with this vegan diet you’ll lose some pounds … summertime you’ll put the weight on, wintertime you’ll be starving … the more weight you put on, the better chances of survival in winter … thus better chances of passing on the genetic code that allows you to put the weight on when you can.
If you have plenty of food in winter, then you’ll have to manage your diet … you’ll want to eat … that’s what the DNA is telling you … 20,000 years ago it was a matter of surviving … today it’s not … adjust
Not just allows you, but compels you with very hard-to-ignore drives. In the same way that fear compels you to avoid scary shit and sexy stimuli compel young adults to really want to get it on, the hunger drive is one of those things that’s critically important to ensuring that your genes get passed on, and so it’s a real bitch to not eat when that drive kicks in. A hominid who could lackadaisically say “meh, I’ll eat/flee/fuck later” starved/got eaten/didn’t get laid with as much certainty as his more forcefully motivated brethren; any individual within whom these drives were not terribly compelling were not as likely to survive.
why yes. It involves hormones. In most people, if they gain weight they actually stop being hungry. Fat cells release a hormone called leptin that travels to the brain and reduces the appetite. Some people develop something called leptin resistance and their brains stop responding to leptin and they continue to be hungry. Here’s a short summary:
What’s really remarkable about this question is that it’s actually a flaw in everything except evolution. The theory of evolution provides a simple explanation for why we work this way, as described above: In the environment in which we did most of our evolving, this behavior was beneficial. But no other explanation can account for it. One might as well call it, for instance, a flaw in intelligent design.
That’s generally true, but being fat isn’t an automatic death sentence. The Venus of Willendorf was made about 25,000 years ago. Whoever carved it must have had real life models as a reference, so even in the Stone Age, at least one person in the tribe could be that much overweight and survive (possibly as a revered queen/goddess or something whose needs were attended to by the rest of the tribe).
A lot of our attitude towards fat is cultural. When I was in Nigeria in the 1970s, a fat belly was considered a sign of wealth among the men, indicating that they were rich enough to eat as much as they wanted. There was no thought of slimming down. They wanted to proclaim their wealthy status to everyone.
Your entire metabolism switches into conservation mode before it starts cannibalizing your fat reserves. Food and fat are not the same, and your fat deposits do not work like a cars has tank. Do not expect your body to function the same way when you are being starved. This is a feature, not a bug.
The thing that puzzles me is why starch tastes so bland. Is it because we evolved eating fruit, and eating starch is a relatively modern thing of the last few dozen millennia?
The real point is - at what point should a “stop” kick in? OP suggests 20lb is too much. I probably haul around 50 to 80lb too much, but then a desk job, unlike running down gazelles in the Serengeti, does not create opportunities to remove that. I have to make the effort. Don’t look at it as “why isn’t there an ‘off’ button?” It’s more to the point that at what point should there be an off button? I probably eat twice what I could survive on - but I don’t eat 4 times as much; I don’t stop at every McDonalds for a full meal between work and home. I don’t spend all my leisure time preparing food.
One obvious “off” button is total stomach capacity. Coney Island hot dog contests demonstrate that we have extremely high limits for total capacity; but we do reach a point of unomfortableness after eating too much.
Another factor is that often, we eat not for hunger, but for other psychological reasons, such as - sugar and or fat will help assuage depressive thoughts. The “ice cream after a breakup” cliché is not far off. to counter that we’d need not a “had enough” trigger but a serious “I don’t want to eat” trigger. The latter is seriously anti-survival.
