Agreed, nutritional "science" and conventional wisdom has become a joke.
http://wholehealthsource.blogspot.com/2011/08/carbohydrate-h...
James Krieger's critique of the core chapter of GCBC is very worthwhile reading: http://weightology.net/?p=265. His blog also has other articles addressing the core Atkins-Taubes thesis of the link between insulin, carbs and obesity. Alan Aragon's Research Reviews had an Editor's Cut on Taubes, as well as pieces specifically on the role of insulin and carbs in obesity and weight gain, but unfortunately all that is subscriber-only. Lyle McDonald (who literally wrote the book on ketogenic diets) has also written a lot on that whole orbit of ideas--never an article against GCBC directly, though he has certainly expressed his negative opinion of it on many occasions.
However, I think most of the book is still worth reading, especially the history behind the demonitization of fat and the uselessness of "calories in, calories out." Taubes is at his best as a science historian and, obviously, not a scientist.
There's nothing useless about energy balance. It can be misinterpreted and misapplied, but Taubes throws the baby out with the bathwater and pretends it doesn't apply at all. For example, classical low-carber mythology is that on a low-carb diet you can eat virtually unlimited calories (as usually defined) and maintain weight, if perhaps not lose weight outright. As an example, there's an old post on Michael Eades's blog where he talks of a small woman allegedly eating 5000 calories and maintaining her weight. As explained in James Krieger's article, people's reports of their own calorie intake for studies have consistently been found to be way off the mark, to the point of being useless. When you actually measure what is being eaten under clinical conditions, the result is in line with the conventional theory of energy balance.
The main benefit of low-carb diets for weight loss is that they spontaneously reduce calorie intake by cutting out whole groups of foods (by looking at studies it's been shown that any diet that restricts food choices like this will tend to induce weight loss but is usually unsustainable), and especially lots of highly palatable foods (to use Guyenet's terminology). But most longer-term comparative studies of diets that look at the performance past the 12-month mark show that low-carb diets don't fare any better on average than other standard weight-loss diets. The one exception is a study the low-carbers like to hold up as a vindication of their views; Lyle McDonald addresses that one here: http://www.bodyrecomposition.com/research-review/comparison-....
Two other pertinent articles by McDonald are http://www.bodyrecomposition.com/fat-loss/is-a-calorie-a-cal... and http://www.bodyrecomposition.com/fat-loss/the-energy-balance....
His main claim is that the energy balance problem is a consequence of getting fat, not the cause.
> Low-carber thesis is that raising intake of fats suppresses appetite so you can eat what you like until you are full.
Eating pounds of fruits and vegetables won't you make you full? Or rice and potatoes for that matter? Eating pounds of lean protein sources like tuna and chicken breast won't make you full?
> The idea is carbs keep you hungry because of energy partiioning and so you over consume calories because you feel hungrier than you should.
That isn't borne out by the evidence. The demonization of one macronutrient over another is baffling. If you subsist on calorically dense processed foods that are purposefully engineered to be high in palatability then you are more likely to overeat. Carbs aren't the problem. Neither is fat; dietary fat is very calorically dense, so it's easy to get lots of "hidden" calories from it, but that's the main downside from a weight loss perspective.
It's not as simple as X is good, Y is bad.
I didn't claim otherwise
Fat accumulates due to an excess of calories. But this isn't the cause of us getting obese, it's a proximal cause, not the ultimate cause. 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.
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.
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.
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.
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.
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
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.
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.....
Remember that your body doesn't care that you want to look good on the beach. It wants to load up when times are good, incase there is a famine around the corner. Piling on the pounds is a survival mechanism, people who tend towards fat are in fact highly tuned survival machines.
It's too soon to tell if this is still a useful mechanism. Mankind has only been "civilized" for a heartbeat in evolutionary time. Nevertheless, if you want to shed fat, the key is to convince your body that starvation is not around the corner.
Eating pounds of fruits and vegetables won't
you make you full?
In some days I eat meat and diary. In other days I eat fruits and vegetables only. I also have days where I allow myself to eat whole-grain bread or pasta. The only days in which I don't feel hunger are the days when I eat meat. If I eat for instance pasta, or potatoes, or rice, in 2 hours tops I get hungry again. Of course, if I eat beans or spinach ... these vegetables keep me full longer than rice, but I still get hungry.
So the issue here is that meat and diary get digested slower. Beans and spinach also get digested slower than bread or pasta or refined carbohydrates, while having better nutritional value (because of the extra fiber).
It's really not about the quantity.
Btw, I also eat high-fat pork meat as I really enjoy it. I have no problems with cholesterol or other issues. I think the secret to a healthy life is having a diverse diet + abstaining from preprocessed crap.
On the last point, of course it's wrong. I never saw Taubes deny CICO as being true. He repeatedly states that, while true, it isn't useful for answering _why_ people get fat.
It's as if I asked why some people are rich and others are poor. And you simply said that the poor people spent more money than they took in. It's true and yet utterly useless if you keep harping on that single point while ignoring inheritance, education, mental illness, drug abuse etc.
You've further convinced me not to recommend GCBC to anyone, since I keep realizing its possible for people to miss the central point of the book.
I'm totally in agreement on Guyenet's stuff, but he agrees with Taubes on CICO being not helpful:
>This is where I agree with Taubes-- 1) the key thing to understand is what is causing the energy imbalance, and 2) the idea that "eat less, move more" is a practical fat loss strategy does not necessarily follow from the first law of thermodynamics. Taking in less energy and expending more does cause fat loss, but the problem is that it's difficult to maintain-- the body opposes changes in its fat stores.
I hate how grains make me feel so I am not going back. Losing weight is a side effect of having more energy via cutting out food that was toxic for me to be eating. This isn't religion but just empirical testing on my part. If it didn't work I wouldn't do it.
Another benefit is that the low-carb diets provide better satiety. In studies, if people were advised to eat ad libitum, those who had to choose from low-carb foods eventually consumed less calories than those, who could choose from "regular" food.
http://paleohacks.com/questions/49970/how-do-we-reconcile-st...
Taubes also responded to Guyenet: http://garytaubes.com/2011/11/catching-up-on-lost-time-%E2%8...
Guyenet also responded to Taubes: http://wholehealthsource.blogspot.com/2011/11/brief-response...
I find Guyenet's arguments much better researched and more convincing. Taubes usually admits he doesn't have time to keep up with the research lately.
My favorite example is Vitamin B12, mostly because I learned the story when I reduced my meat consumption to about once a month. So there's this family of massive molecules containing the metal cobalt which we can't make on our own because we're not adapted to eat cobalt, and they're all called "Vitamin B12". It helps in the last step of making the protein building-block called methionine; if you get malnourished in this way your body just basically fills up with "almost finished" methionine which is useless and might even be poisonous. There can also be a slight risk of nerve damage although as I understand it we don't actually understand why the hell that would be.
The biggest cause of malnutrition in this sense is simply being old -- you can't absorb Vitamin B12 so well in the first place because it is huge and weird, and old people have even more trouble either because their gut is slowly dying or because they're infected with H. pylori, which is a safe bacteria more than 80% of the time and might even be important for a well-functioning stomach, but might sometimes cause a chronic tummy-bug.
Okay, so that's the problem, but what do we know about how much of the B12s we need and get? We know very little. The US Recommended Daily Allowance of B12s is 2.4 μg, but the US Daily Value for B12 is 6.0 μg. How much do you get in your food? You get almost none from vegetables, and vegans are basically all ipso facto suffering from B12 deficiency unless they take supplements or eat enriched cereal -- but most of them are quite healthy and see no problems from it. As for vegetarians like (almost-) me, the exact range for milk and eggs to get to this limit is imprecise because the limit itself varies by a factor of 3, so you might need to eat three eggs per day or else ten; so you might need to drink two cups of milk per day or else five, to live up to those numbers. So in theory there are lots of vegetarians also who come in at half or one-third their daily requirement, and never notice anything. Meanwhile there are people over 60 who eat plenty of meat but are starting to feel the effects anyway.
We actually don't even know how well you absorb it. A USDA researcher named Lindsay Allen did a 2011 study where she marked Vitamin B12 in eggs so that she could detect it, and then fed those eggs to 10 people. She found that the body absorbed 50% of a 1.5 μg dosage but only 20% of a 2.6 μg dosage. Let me repeat that. She found that, in absolute value terms, eating more B12 led to less of it being absorbed, 0.75 μg versus 0.5 μg. It's probably not statistically significant with 10 people, but still. We don't even know that eating more leads to you absorbing more of it. (I also wonder whether RDAs are "amount absorbed" while DVs are "amount eaten", as this is pretty much never reported, but I will assume that they aren't crazy and that it's always "amount eaten.")
I wouldn't use the scare-quotes around "science" when talking about nutrition science, as I think there is potential for real research here and I think people do indeed do it -- but it's a lot of work before we have a firm understanding, and most of that work hasn't been done yet, and yet you hear these confident conclusions. I would just like to hear people publish standards in the form, "you might need this much, or that much, we don't really know."
The engineer in me craves error bars. Where are the error bars?
It is perhaps ironic that marmite is also loaded with sodium. So... if we take this article at face value it's win/win!