> What causes us to eat more calories than our bodies require?
One big reason is eating foods that aren't filling relative to the energy and nutrients they provide. There's nothing unique about carbs in that regard. I can barely put away a 1000-calorie meal with an equal amount of calories from chicken breast and white rice (100+ grams of carbs just from the rice). Putting away the same amount of calories split between chicken breast and greens would be almost physically impossible--I ate a whole pound of grilled asparagus with my chicken breast on Sunday, and the asparagus barely amounted to 100 calories. But I can easily put away a 2000-calorie pepperoni pizza with extra cheese. If you think carbs are the calorically-dominant macronutrient in that pizza, think again. I'm not blaming the fat either. My point is that the issue goes much deeper than simple macronutrient composition.
Fats and proteins are more filling and satisfying per gram than carbs.
The pizza example you give is basically wrong. Carbs would be the largest source of calories. For example see http://nutritiondata.self.com/facts/fast-foods-generic/9307/... which is for a 2500 calorie pepperoni pizza. Almost half the calories come from carbs.
> Fats and proteins are more filling and satisfying per gram than carbs.
Again, that statement makes no sense. You don't eat carbs, fats and proteins. You eat foods. Is 100 calories of olive oil as filling as 100 calories of asparagus (about a pound)? If that's too extreme, I'd still gladly put up your 100 calories of olive oil (a few spoonfuls) against my 100 calories of white rice (a small bowl) for satiety and fullness.
Different macronutrients stimulate hormones differently, so I'm not saying that macronutrient composition doesn't play a role in these matters, only that those effects are mostly irrelevant if you don't go overboard. For example, high GI and low GI foods have virtually identical glycemic loads when consumed alongside a lean protein like chicken breast (GI is measured by feeding food to a subject after a 12-hour fast), so even if you accept that insulin is the master regulator of fat storage (which is out of date nonsense that Taubes can't get out of his head), it still wouldn't matter appreciably so long as you eat your carbs alongside your fiber and protein.
> The pizza example you give is basically wrong.
I was going by the pizza recipe I usually make at home, which per slice has 200 calories from fat and 100 from carbs.
You seem to know what you're talking about. Is there a book, author, or website you'd recommend for getting a primer on nutrition? Many of my friends are doing paleo diets, juice diets, no-carb diets and all of them have pseudo scientific sounding explanations and bestselling books espousing them.
I don't personally need to lose any weight (in fact I could stand to gain a few) but I am still curious about how the food I eat is affecting my body. With everyone yelling different sets of "facts", it's hard to know where to even start.
Lyle McDonald is the best source out there. His website at http://bodyrecomposition.com has a near-endless wealth of articles. Alan Aragon's work (http://alanaragon.com/) is on a similar level, and in many ways he's a kinder, gentler version of Lyle. However, his best stuff is only available as part of his subscriber-only Alan Aragon's Research Review. James Krieger is another one whose website at http://weightology.net I already referenced elsewhere in this thread.
As a rule, the people whose work I lean on are those with both a deep knowledge of the underlying theory as well as clinical experience working with a range of athletes and non-athletes. Of course, you should never trust anyone unconditionally and always evaluate their reasoning on its own intrinsic merits. Someone like Charles Poliquin seemingly fits my description, but he makes most of his money from selling supplements and is always pushing his products--he recommends that you consume massive doses of his insanely overpriced fish oil, rub licorice cream on your abdomen for spot-reduction fat loss, etc--so everything he says must be taken with a truckload of salt.
People like Robb Wolf and Mathieu Lalonde from the paleo community also fit my desiderata. You can learn a lot from them, so long as you keep in mind that most of their clinical inferences are so far by necessity based mostly on anecdotal data rather than controlled studies. There are also some general issues to keep in mind with the ancestral dietary approach as generally preached and practiced. There's an underlying assumption that the ancestral diet was far more uniform across cultures than the evidence shows. They also tend to downplay the evidence that grain consumption has been around for much longer than 10,000 years, indeed closer to 100,000 years, giving plenty of time for many physiological adaptations to have taken place. Stuff like that. As with everyone with strong commitments to a specific point of view, their analysis is often subject to confirmation bias. A classic case would be Robb's analysis of the traditional Okinawan diet where he completely downplayed the very high levels of carbs consumption via rice by giving virtually all the credit for the health benefits to the fatty fish consumption.
His statement was on a per-gram basis, which seems pretty much obviously true (since it basically says that fat is more energy-dense than carbs).
Nonetheless, like jcheng I'm interested in what you've learned from your research. I've also been looking into low-carb/ketogenic diets, and a friend does intermittent fasting (IF), and there are a host of clashing opinions and studies of varying quality on everything. Taubes, Lustig, Aragorn...my conclusion is that we still know very little about the effects of diet composition.
I've switched mostly to sugar substitutes and reduced my carb intake because it seems like something most would agree upon. My IFing friend claims IF/caloric restriction is one of the few things actually shown to significantly prolong lifespans in animals. Do you have any knowledge of these things, or of better-done studies I should be reading? Thanks.
edit: I've just been reading Guyenet and what he says is quite interesting
> His statement was on a per-gram basis, which seems pretty much obviously true
Ah, I missed that. But that's not very a useful comparion. The useful thing to do is comparing calorically matched portions of fat-based and carb-based foods for satiety and fullness.
One problems with carbs though, particularly carbs that break down fast in the body (say, rice or honey) is that they do cause insulin spikes and blood sugar drops, which can often lead to additional consumption. Carbs are unique in this regard though to varying degrees: coconut sugar seems to have very little of this effect while rice is very bad. There's a reason why Chinese food is associated with folks being hungry an hour after eating.
However, I think the real harm comes from combining the carb boom-and-bust blood sugar cycle with high diets where it's easy to eat lots of calories, and when you add a sedentary life style by historical terms, it gets even worse.
A hundred and fifty years ago, the average Irish peasant would have eaten 12 pounds of potatoes every day. That's almost 5000 calories just from the potatoes (and now add a small amount of dairy, veggies, and eggs).
So it's not just one thing. It's the emphasis on carbs, the concentrated energy foods, and the fact that we drive in cars and dont walk that much and certainly don't try to grow our own food in marginal rocky soil.....
Edit: I always wondered why Javanese food is traditionally so sweet without a lot of people being obese. It turns out that the biggest sweatener used is coconut sugar, which has a glycemic index of something like 35. That's a bit higher than whole barley but quite a bit lower than wheat.....
One big reason is eating foods that aren't filling relative to the energy and nutrients they provide. There's nothing unique about carbs in that regard. I can barely put away a 1000-calorie meal with an equal amount of calories from chicken breast and white rice (100+ grams of carbs just from the rice). Putting away the same amount of calories split between chicken breast and greens would be almost physically impossible--I ate a whole pound of grilled asparagus with my chicken breast on Sunday, and the asparagus barely amounted to 100 calories. But I can easily put away a 2000-calorie pepperoni pizza with extra cheese. If you think carbs are the calorically-dominant macronutrient in that pizza, think again. I'm not blaming the fat either. My point is that the issue goes much deeper than simple macronutrient composition.