I don't understand the problem with eating what you feel like when you're hungry, and stopping when you're full. You'd think a billion years of evolution would enable us to find a decent equilibrium by listening to our bodies. Obviously, it's the stopping when you're full part that's hard...
I find your dismissiveness to be disheartening. This isn't the usual fad diet nonsense. This is actually a finding that could be extremely interesting to researchers who work on longevity.
This study fits in with a large array of similar research on other species of mammals. Many of them have found that calorie restriction is associated with a significant extension of lifespan in the model species being used.
There's also some theoretical underpinnings that render the idea plausible. Free radicals are the cause of a number of processes that we collectively refer to as 'aging'. Since free radicals are a product of metabolizing, the reasoning goes that if you eat less you might produce less free radical in the first place, which in turn might lead to less aging.
If this study is accurate, then it suggests that the aging process in primates may not work quite the same way it does in rodents. And who knows where further research into something like that might go; at the very least learning more about primate biochemistry is a good way to figure out potential new treatments for human diseases.
In fact, calorie restriction doesn't even work well in rodents. One of the articles points out that whether calorie restriction "works" in mice depends on the lineage, some breeds it works and some it doesn't.
On the contrary, we overeat precisely because we listen to our bodies.
Evolution tuned us to survive in a world where food is scarce and periods of starvation are frequent. In the rare occasion that you have excess food, you eat it and build up fat reserves. The saved up fat will help you survive the period of starvation that undoubtedly follows.
So why isn't there a decline in appetite as the fat reserves grow? It won't matter while there are no side effects of adding more fat, but there seems to be a widespread belief that fat causes all sorts of health problems. At the least there is decreased mobility (more likely to be eaten by lions), earlier mortality (eg heart attacks) etc.
I wonder if there are any studies correlating obesity levels with reproductive success, and success of the offspring produced. That is what should end up controlling the genes and behaviour behind all this.
That would work if food were equally calorie dense. My stomach can hold about 3 cups of food most days. I can eat 3 cups of mashed potatoes (640 calories) or 3 cups of sugar (2326 calories) to feel full.
We didn't have processed cane sugar and refined vegetable oils during all those years of evolution.
The feeling of satiety is not just a function of how full your stomach is. It's also a function of blood sugar levels. If you were eating sugar, you would start feeling full a lot sooner than if you were eating mashed potatoes. As a result, you would eat less of it in volume. (This is why sweet things are almost always served as desert, so they have a "topping off the satiety" effect as opposed to "killing the appetite before the real meal" effect.)
The danger here is calorie-dense fatty foods. Things like almonds and cashews are ridiculously easy to overeat, because they take up relatively little space and have a very tiny effect on blood sugar levels.
"The feeling of satiety is not just a function of how full your stomach is. It's also a function of blood sugar levels."
No, it is not. Satiety is a complex process mediated and regulated by a certain number of hormones. Leptin controls satiety, whilst the release of ghrelin induces the feeling of hunger. There is no difference between eating pure sugar and potatoes, as the latter breaks down mostly into glucose, anyway. Eating both will give a blood sugar spike but won't stop you from gorging on both unless your body promptly starts releasing leptin.
>The danger here is calorie-dense fatty foods. Things like almonds and cashews are ridiculously easy to overeat, because they take up relatively little space and have a very tiny effect on blood sugar levels.
I wouldn't say that's the danger. How many overweight people got that way because they eat too many cashews vs. guzzling liters of soda?
And soda (and beer, wine, milk, every liquid with sugar in it) doesn't provide any feeling of fullness. Our species hasn't had to evolve around caloric liquids until about 3000 years ago.
The trouble with this viewpoint is it seems to assume that evolution is optimizing for longevity. That fact is very much lacking from the evidence. Many creatures are literally programmed to die as soon as they finish reproducing. This is obviously not the case for humans, but it does show that evolution does not necessarily have our individual best interests at heart.
When we talk about longevity these days, we're not talking about living long enough to raise children — we're talking about living way past the point where we serve any clear evolutionary purpose. Thus, evolution might not be the best guide.
You could make some of the same arguments about animals that die immediately after mating or giving birth (e.g. they could have more kids too). Clearly that doesn't save them.
You seem to be tightly focusing on a possible reading† of the second-to-last sentence of my comment. I'm not sure why. It doesn't matter if older people have zero evolutionary benefit or simply less evolutionary benefit — the point is that evolution does not necessarily optimize for longevity (certainly not to the point where we can't do better than simply looking at how our basic instincts).
† I actually anticipated a response like this, which is why I added "clear." The evolutionary benefit of a grandparent is a lot less clear-cut and immediate than the benefit of a parent. Clearly I still did not communicate that well enough.
It still seems to me that this is all a red herring, and you're ignoring the overall thrust of my comments to argue with a point I did not even really make. As I said, whether grandparents offer zero evolutionary benefit or simply less evolutionary benefit than immediate parents is immaterial.
My point is that nobody has yet presented enough evidence to argue that simply "listening to our bodies" rather than taking any proactive measures is the best path to longevity. The view that evolution has given us natural lifespans that are as long as can be doesn't seem to be supported by the evidence.
Calorie-restricted diets that are being studied for life extension involve stopping before you're full. Other animal models had suggested that calorie-restriction would extend maximum lifespan beyond normal, anywhere from 20-50%. This is very different from just eating a normal healthy diet and stopping when you're full.
If you take the diet people used "a billion years" ago, it is definitely easier to control your hunger/cravings. But that would mean giving up on sugar (yup, juices and most fruit included), all sorts of bread and grains, potato, chocolate, beer, etc - all foods that alter your body levels and make self-control a struggle in the likes of an ex-smoker entering a room full of people smoking their lungs off.
TL;DR version: eating the right things can help you stopping when you're full...
A recent Horizon (BBC) documentary described some evidence that not everybody gets the 'full' signal in the same way or with the same strength.
If this is right then your advice will work for a significant proportion of the population (maybe even a majority) but that it won't work for everybody.
Supposedly, when you're full, you feel vaguely satisfied. When you actually feel full, you're actually overfull. When you feel stuffed, you're over-overfull.
Comments
I don't understand the problem with eating what you feel like when you're hungry, and stopping when you're full. You'd think a billion years of evolution would enable us to find a decent equilibrium by listening to our bodies. Obviously, it's the stopping when you're full part that's hard...
I find your dismissiveness to be disheartening. This isn't the usual fad diet nonsense. This is actually a finding that could be extremely interesting to researchers who work on longevity.
This study fits in with a large array of similar research on other species of mammals. Many of them have found that calorie restriction is associated with a significant extension of lifespan in the model species being used.
There's also some theoretical underpinnings that render the idea plausible. Free radicals are the cause of a number of processes that we collectively refer to as 'aging'. Since free radicals are a product of metabolizing, the reasoning goes that if you eat less you might produce less free radical in the first place, which in turn might lead to less aging.
If this study is accurate, then it suggests that the aging process in primates may not work quite the same way it does in rodents. And who knows where further research into something like that might go; at the very least learning more about primate biochemistry is a good way to figure out potential new treatments for human diseases.
In fact, calorie restriction doesn't even work well in rodents. One of the articles points out that whether calorie restriction "works" in mice depends on the lineage, some breeds it works and some it doesn't.
Modern food availability and composition differs wildly from what we evolved on for 99.999% of that billion years.
It's not a big surprise that finding an equilibrium in this relatively new food and mobility environment is difficult for our species.
On the contrary, we overeat precisely because we listen to our bodies.
Evolution tuned us to survive in a world where food is scarce and periods of starvation are frequent. In the rare occasion that you have excess food, you eat it and build up fat reserves. The saved up fat will help you survive the period of starvation that undoubtedly follows.
So why isn't there a decline in appetite as the fat reserves grow? It won't matter while there are no side effects of adding more fat, but there seems to be a widespread belief that fat causes all sorts of health problems. At the least there is decreased mobility (more likely to be eaten by lions), earlier mortality (eg heart attacks) etc.
I wonder if there are any studies correlating obesity levels with reproductive success, and success of the offspring produced. That is what should end up controlling the genes and behaviour behind all this.
That would work if food were equally calorie dense. My stomach can hold about 3 cups of food most days. I can eat 3 cups of mashed potatoes (640 calories) or 3 cups of sugar (2326 calories) to feel full.
We didn't have processed cane sugar and refined vegetable oils during all those years of evolution.
The feeling of satiety is not just a function of how full your stomach is. It's also a function of blood sugar levels. If you were eating sugar, you would start feeling full a lot sooner than if you were eating mashed potatoes. As a result, you would eat less of it in volume. (This is why sweet things are almost always served as desert, so they have a "topping off the satiety" effect as opposed to "killing the appetite before the real meal" effect.)
The danger here is calorie-dense fatty foods. Things like almonds and cashews are ridiculously easy to overeat, because they take up relatively little space and have a very tiny effect on blood sugar levels.
edit: wow, why the downvotes?
"The feeling of satiety is not just a function of how full your stomach is. It's also a function of blood sugar levels."
No, it is not. Satiety is a complex process mediated and regulated by a certain number of hormones. Leptin controls satiety, whilst the release of ghrelin induces the feeling of hunger. There is no difference between eating pure sugar and potatoes, as the latter breaks down mostly into glucose, anyway. Eating both will give a blood sugar spike but won't stop you from gorging on both unless your body promptly starts releasing leptin.
>The danger here is calorie-dense fatty foods. Things like almonds and cashews are ridiculously easy to overeat, because they take up relatively little space and have a very tiny effect on blood sugar levels.
I wouldn't say that's the danger. How many overweight people got that way because they eat too many cashews vs. guzzling liters of soda?
I should say it is a danger, rather than the danger. Poor wording on my part.
In any case, more people get fat off guzzling soda because soda is significantly cheaper, and are served in virtually every restaurant.
And soda (and beer, wine, milk, every liquid with sugar in it) doesn't provide any feeling of fullness. Our species hasn't had to evolve around caloric liquids until about 3000 years ago.
The trouble with this viewpoint is it seems to assume that evolution is optimizing for longevity. That fact is very much lacking from the evidence. Many creatures are literally programmed to die as soon as they finish reproducing. This is obviously not the case for humans, but it does show that evolution does not necessarily have our individual best interests at heart.
When we talk about longevity these days, we're not talking about living long enough to raise children — we're talking about living way past the point where we serve any clear evolutionary purpose. Thus, evolution might not be the best guide.
[deleted]
You could make some of the same arguments about animals that die immediately after mating or giving birth (e.g. they could have more kids too). Clearly that doesn't save them.
You seem to be tightly focusing on a possible reading† of the second-to-last sentence of my comment. I'm not sure why. It doesn't matter if older people have zero evolutionary benefit or simply less evolutionary benefit — the point is that evolution does not necessarily optimize for longevity (certainly not to the point where we can't do better than simply looking at how our basic instincts).
† I actually anticipated a response like this, which is why I added "clear." The evolutionary benefit of a grandparent is a lot less clear-cut and immediate than the benefit of a parent. Clearly I still did not communicate that well enough.
[deleted]
It still seems to me that this is all a red herring, and you're ignoring the overall thrust of my comments to argue with a point I did not even really make. As I said, whether grandparents offer zero evolutionary benefit or simply less evolutionary benefit than immediate parents is immaterial.
My point is that nobody has yet presented enough evidence to argue that simply "listening to our bodies" rather than taking any proactive measures is the best path to longevity. The view that evolution has given us natural lifespans that are as long as can be doesn't seem to be supported by the evidence.
It seems that we just don't understand each other then. Sorry for wasting your time.
Calorie-restricted diets that are being studied for life extension involve stopping before you're full. Other animal models had suggested that calorie-restriction would extend maximum lifespan beyond normal, anywhere from 20-50%. This is very different from just eating a normal healthy diet and stopping when you're full.
If you take the diet people used "a billion years" ago, it is definitely easier to control your hunger/cravings. But that would mean giving up on sugar (yup, juices and most fruit included), all sorts of bread and grains, potato, chocolate, beer, etc - all foods that alter your body levels and make self-control a struggle in the likes of an ex-smoker entering a room full of people smoking their lungs off.
TL;DR version: eating the right things can help you stopping when you're full...
A recent Horizon (BBC) documentary described some evidence that not everybody gets the 'full' signal in the same way or with the same strength.
If this is right then your advice will work for a significant proportion of the population (maybe even a majority) but that it won't work for everybody.
Put simply, a billion years of evolution did not prepare us with thousands of calories of readily available, calorie dense (fast-)foods.
The problem is that a lot of people (myself included) are not very good at knowing when we're full.
Supposedly, when you're full, you feel vaguely satisfied. When you actually feel full, you're actually overfull. When you feel stuffed, you're over-overfull.