Why Are We So Fat?

Great Debates
1

This is xposted from another thread about human obesity on this MB.
Let’s say we have critter A and critter B. Critter A can store unlimited amounts of fat. Critter B will be sleek and thin for life. It will always eat reasonably meals and stop eating the moment it gets full. Yay Critter B, right?

But wait! Bother of these creatures live in an environment where the food supply is erratic. Sometimes there’s lots, and sometimes there’s none.

Critters A and B stumble upon a large supply of food.

Critter B has a nice, sensible meal, and buggers off.

Critter A completely oinks out, eats a HUGE meal, and rests content in knowing that most of that meal will be converted to fat.

Contented? But fat is BAD! Or is it?

Critters A and B will go a long, long time before finding any more food. Critter A has heavy fat reserves, which are like money in the bank, biologically speaking. Critter B, however, gets thinner, and thinner, and thinner… Critter B, in fact, might not make it, and certainly will not be in the best of health come spring and mating season, when it’s time for the Darwin Bowl and everyone competes for a mate.

So evolution has heavily selected for the Critter A gene, which makes you take full advantage of any and all food supplies, and furthermore, makes you habitually hungry enough to be highly motivated to find those calories you’re going to need so badly.

Think of the undustrious squirrel, hoarding acorns. But instead of an acord supply just waitng for someone else to come take it, Critter A puts his acorns where he can best defend them and keep an eye on them… on his body.

And this was smart for us humans all the way until the 20th century, and arguably, into part of it as well. Until we got to the point, in some of the world, where famine was unknown, it still made sense to pack on the fat when the food was plentiful, and then live on your fat stores when it wasn’t.

So we’ve had 80 years, tops, for biology to catch up to the change in how we live. We can all, more or less, eat however much we want of whatever we want, whenever we want. And so those old Critter A instincts and metabolisms, which were so useful for millions of years, are now killing us off in large numbers. VERY large numbers.

And that’s why there’s so many fat folks like me around. We actually have extremely good genes… that are just 80 years out of date. :slight_smile:

2

For most of us in the Western world, the food supply has been stable and bountiful for much longer than that.

I happen to think it really has to do with lack of exercise.

It’s amazing how many calories one uses just walking for a few hours a day. In the modern, sedentary world, it’s dangerously easy to eat beyond our daily need.

3

So you know that eating too much is bad for you, and you could die young because of it. But you believe this is a good thing from a genetic perspective?

We can all drink as much alcohol or ingest as much illicit drugs as we want to, money permitting --same as food – but we manage to exercise control most of the time on these fronts.

Why the hell should gorging on unhealthy amounts of food be any different?

4

Well obviously it has to do with lack of exercise. :slight_smile: I’m not claiming that my explanation somehow justifies stuffing your face and dropping dead at fifty.

I’m just providing an explanation as to how we got here.

5

No no… it used to be a good thing from a genetic perspective. Up until the agricultural revolution, it was a bloody fantastic thing. And even after, it would be the Critter A types who survived famine.

Now, in the modern world, in this present day, it’s these exact tendencies, that worked so well for so long, that are killing us by the millions, especially big fat white guys like me.

And the prospects of solving the problem are daunting. We’re up against millions of years of evolution. We haveb’t the slightest idea how to convince large number of free citizens to change their habits, you can educate all you want. Smokers know it’s killing them, and fat people know it’s killing THEM. That does not make it any easier to change.

And evolution won’t help. Sure, obesity kills. But it gives you plenty of time to have kids before that. Sorry, Darwin.

Honestly, the only realistic hope is technology. A fat blocking pill, a miracle food technology, something along those lines.

6

How long though? The British agricultural revolution is only about 250 years old. And besides, even if food was plentiful in spring or summer, winters in the 16th century were likely very lean for most people.

7

Because we didn’t evolve over billions of years to get adequate alcohol in our systems, lest we die.

The failure rate for voluntarily controlling food intake as a means of weight control is roughly 98%. A person is more likely to get into and graduate from MIT than lose a significant amount of weight and keep if off with voluntary food control.

The two biggest failures of western medicine occurred when doctors told their patients to not have sex (abstinence) and to eat fewer calories than their bodies felt they needed (dieting). Both abstinence and dieting have failure rates of well over 90%. It is no coincidence that asexuality and starvation are (along with trauma) the biggest threats to biological survival. You might as well ask people to hit themselves in the head with a hammer each morning at 5am and be surprised when the failure rate for compliance with that is 98%.

8

As someone who lost 35 pounds last year, it’s because we eat more and exercise less. Once I found a website to help me quantify how much I eat and exercise, the weight came off, and has stayed off for more than five months now.

I also think restaurants have been increasing their portion sizes. I heard once that a McDonald’s Kids Meal hamburger is the same size as a regular adult hamburger from a few years ago. A serving of meat is three ounces, but I defy you to find a steakhouse that will serve a steak that small.

9

poor eating habits.
lack of regular exercise
laziness as a way of life
loss of shame in being a fatass

10

That would be the eating more than required regardless of factors such as lifestyle, genetics, metabolism, excuse, excuse etc.

If you don’t eat more than you require you don’t gain weight.

11

Is anyone eating something highly caloric for recreational purposes between meals while reading this thread?

Thought so.

12

The Happy Meal burger has always been the regular adult hamburger size, a 1/10 lb. patty.

13

I don’t think you know many fatasses.

14

To try to clear things up a tad :

Yes, I know that the immediate cause for being being obese is that people eat too much and do too little. What I was trying to address in the OP was what causes it from a longer view. Why do some people eat far too much, far too often? Why don’t they feel full sooner? How come this tendency still exists in us? What possible use could evolution have for the ability to pack on so much fat? etc etc.

My answer for that is, these tendencies were very adaptive, evolutionarily speaking, until fairly recently in human history. Biologically speaking, it’s been an eyeblink since we were scraping bare subsistence out of crude farms. The ability to eat unlimited amounts, opportunistcally, and store that caloric power for later, was extremely handy.

But Nature never foresaw a time of continuous, unlimited plenty. Use overweight people are building up reserves for a winter famine that never comes. Nature certainly never imagined a time when we could pack on so much stored fat that it actually became a serious health problem and made us sick and weak. In Nature, in order to get that many calories, you’d have to work pretty damned hard, and it would even out. Not so any more.

So the tragic truth is that no matter what science tells us, and what we know to be true, it’s up against the voice of biology and genetics, which keeps telling us that what we are doing when we eat too much is exactly the right thing to do.

Hopefully, science will find osme sort of “off switch” for that.

15

Incidentally I was trying to tackle this sort of pseudo-scientific thinking in another thread just a couple days ago. I don’t believe a word of it. Do we have a gene which causes some people to gorge themselves while others eat sensibly? Well, can you tell me where the gene is? Finding them should not be difficult. All you have to do is round up 500 overeaters and 500 moderate eaters, do genetic surveys on them, and find the allele where the first group all have one gene while the second group all has another gene.

Furthermore, there are obvious problems with the explanation. Why is obesity so much higher in the United States than in many other wealthy countries, such as Japan or Western Europe? It’s surely not because of differences in wealth; famine is unknown in all first-world countries. According to your reasoning, evolution should have selected the gorging genes everywhere. In reality, there are no such genes, only free will. People in Japan or France or Norway simply choose to eat smaller portion sizes of healthier foods and to exercise more.

One could make the same point within the United States. Obesity is much more common among the poor than among the rich, which flies in the face of your theory. The rich certainly have access to a lot more food, so if your theory was right they’d be the ones ballooning outwards due to overeating.

My explanation would go like this. Back in ye olden days, people generally believed that eating was a moral issue. They listed gluttony as a sin and eating light as a virtue. This view gave them the strength to exercise self-control when they ate. Nowadys most people would call that viewpoint archaic; many are not even aware that such a viewpoint exists. Consequently people have no motivation to control their eating (except for health reasons, and that’s not usually a strong enough motivation.)

This theory can explain the data. Why are the poor much more likely to be obese, while the rich remain thin? Because the rich still learn some amount of self-control through their advanced education, while the poor generally do not. Why are Americans fatter than anyone else? Because America has a me-first, capitalist culture which encourages us to indulge our every want, while other cultures are more focused on responsibility.

16

While I don’t think there’s a “fat” gene, I can agree with the OP about this being a tendency that is part of human nature. Our current weight crisis is the result of animal survival instincts (must eat everything we can and conserve energy) with the fact that our society has made these goals far too easy (we can easily get an excess of calories with little effort and don’t typically have to expend much energy in our daily lives).

Luckily, those same abilities that allowed us to create a society geared towards fulfilling our lazy, ravenous desires also enable us to control our instincts to a degree. Like ivylass mentioned, having a way to quantify what we eat and how much we exercise can help tremendously.

17

The answer is likely ‘we don’t know’. If we knew how obesity worked from a biochemical perspective, we would likely have a cure for it. The fact that everything short of surgery has a failure rate of nearly 100% as a long term cure for obesity shows we really have no idea why or how it works. Much obesity research is only 20 years old at oldest, and it is a field we understand little about.

I think you are making assumptions based on stereotypes. Fat people are considered lazy, immoral, decadent and weak willed in our society. Therefore the cause of obesity is being lazy, immoral, decadent and weak willed. This is circular logic at best.

As a society we’d be much better off if we endorsed healthy lifestyles rather than voluntary weight control, endorsed body tolerance and waited a few more decades until we understood how to cure obesity in a way that actually works. Obesity is far too emotionally charged to be treated as a medical issue the way it needs to be.

18

If you stop breathing you don’t gain weight either, because without oxygen you cannot engage in aerobic ATP production. Anaerobic ATP production uses about 10x more glucose per mol of ATP produced.

So go tell people to voluntarily hold their breath as a way to increase their metabolism and lose weight. And if every study in every medical journal written on the issue shows a 90-100% failure rate, come back and I will blame it on laziness and being weak willed.

19

Michael Pollan covers this quite well in The Omnivore’s Dilemma – basically snack food creators and marketers depend on Americans (and others, of course) never being full so you can remain open to buying whatever new products they put on the market. If you eat three square meals a day, you won’t need muffins in bar form, tubes of chips, pizza pockets, 100 calorie bags of crackers, etc.

I don’t recall if he mentions the diet industry, but I’d say that plays a huge role as well. Americans spend an estimated $46 billion on diet food and merchandise. In the same way we’ve been groomed to demand instant satisfaction in the form of fast food, we want a quick fix when it comes to weight loss – especially since celebrity culture allows for little to no middle ground. If size 10 women were anywhere in the public eye, a size 16 woman might settle for getting there eventually. But if she’s told anything above size 2 is embarrassing, she’s less likely to settle for losing half a pound a week.

20

That was largely true during the late 80’s and 90’s, but portion sizes are going down again. People aren’t actually that good at knowing what an “appropriate” amount of good is without relying on a lot of context clues like plate size. Restaurants have figured out that if they just make it look like you have a lot of food, you’ll walk out just as satisfied and they can save on food costs. Check out Brian Wansink’s “Mindless Eating” for more.

The obesity epidemic is almost entirely cultural. It isn’t because of the sudden influx of food that we can’t resist, but because our (American) society has changed how it looks at food. We don’t stop when we’re full; we stop when the plate is cleared. We don’t stop when lunchtime is over; we might stop off for a mid-afternoon donut and coffee. We don’t walk; we drive. We don’t eat dinner when we’re hungry; we eat dinner when it’s dinnertime. We don’t stop eating at “not hungry”, we stop at “full.” Macaroni and cheese is considered a vegetable.