The reason I'm so fascinated by this book is that, after a lifetime of struggling with weight and eating patterns and being told in various ways that it all comes down to me being a compulsive overeater, lacking in willpower and self-control, and indolent in general, and even in the pro-size anti-dieting literature I've read never quite seeing a logical feasible reason for assertions that fat people eat more no more than lean people or that diets don't work, finally Taubes answers these questions, or points to potential answers that really satisfy my mind. I hope these ideas get disseminated in our culture, but I'm pretty sure that there's so much entrenched medical dogma to the contrary, as well as cultural dogma that relishes hating fat people and passing harsh moral judgment on them, that it's unlikely to get a fair hearing or have a large meta-effect, and that's a tragedy, because it's easy to foresee a lot of suffering in store for fat children being targeted by social engineering in the name of the "obesity epidemic", etc. Taubes makes the point that diet is like religion, in that few other things seem to so universally arouse people's passions, self-righteousness, and defensiveness, so he himself isn't very optimistic that the establishment that has built up its reputation (and he goes into great detail about who these so-called experts are, what their research credentials are, and how they got to be eminent, and it's not exactly on sheer merit) on the low-fat, fat-people-eat-too-much dogma aren't going to let go of that just because the evidence isn't there. (Why let facts get in the way of a good feeling of superiority?)
Now, Taubes does write from a supposition that this epidemic is real, and that obesity is a disease and part of (but not a cause of) other diseases he calls Diseases of Civilization or Western Diseases, principally diabetes, heart disease and cancer, and I know some people will argue that one can be fat and healthy, and I probably agree with that. But since he really goes to great lengths to show that obesity is part of a group of metabolic symptoms, rather than a cause, I think he gets a pass on that.
Here's his summary list of points that are made in the book, followed by a few paragraphs immediately following, all drawn from the book's epilogue:
1. Dietary fat, whether satured or not, is not a cause of obesity, heart disease, or any other chronic disease of civilization.
2. The problem is the carbohydrates in the diet, their effect on insulin secretion, and thus the hormonal regulation of homeostatsis--the entire harmonic ensemble of the human body. The more easily digestible and refined the carbohydrates, the greater the effect on our health, weight, and well-being.
3. Sugars--sucrose and high-fructose corn syrup specifically--are particularly harmful, probably because the combination of fructose and glucose simultaneously elevates insulin levels while overloading the liver with carbohydrates.
4. Through their direct effect on insulin and blood sugar, refined carbohydrates, starches, and sugars are the dietary cause of coronary heart disease and diabetes. They are the most likely dietary causes of cancer, Alzheimer's disease, and other chronic diseases of civilization.
5. Obesity is a disorder of excess fat accumulation, not overeating, and not sedentary behavior.
6. Consuming excess calories does not cause us to grow fatter, any more than it causes a child to grow taller. Expending more energy than we consume does not lead to long-term weight loss: it leads to hunger.
7. Fattening and obesity are caused by an imbalance--a disequilibrium--in the hormonal regulation of adipose tissue and fat metabolism. Fat synthesis and storage exceed the mobilization of fat from the adipose tissue and its subsequent oxidation. We become leaner when the hormonal regulation of the fat tissue reverses this balance.
8. Insulin is the primary regulator of fat storage. When insulin levels are elevated--either chronically or after a meal--we accumulate fat in our fat tissue. When insulin levels fall, we release fat from our fat tissue and use it for fuel.
9. By stimulating insulin secretion, carbohydrates make us fat and ultimately cause obesity. The fewer carbohydrates we consume, the leaner we will be.
10. By driving fat accumulation, carbohydrates also increase hunger and decrease the amount of energy we expend in metabolism and physical activity.
He adds: Evolution should be our best guide for what constitutes a healthy diet. It takes time for a population or a species to adapt to any new factor in its environment; the longer we've been eating a particular food as a species, the closer that food is to its natural state, the less harm it is likely to do. The fat content of the diets to which we presumably evolved will always remain questionable [because we can't know what paleolithic hunter-gatherers ate at all places and seasons]. Recommending that we consume oils is a problem--did we evolve to eat olive oil, for example, or linseed oil? And maybe a few thousand years is sufficient time to adapt to a new food but a few hundred is not. There is no such ambiguity however on the subject of carbohydrates. The most dramatic alterations in human diets in the past 2 million years, unequivocally, are 1) the transition from carb-poor to carb-rich diets that came with agriculture--the addition of grains and easily digestible starches to the diets of hunter-gatherers; 2) the increasing refinement of those carbs over the past few hundred years; and 3) the dramatic increases in fructose consumption that came as the per-capita consumption of sugars--sucrose and now high-fructose corn syrup--increased from less than 10 to 20 lbs a year in the mid-18th century to the nearly 150 lbs it is today. Why would a diet that excludes these foods specifcally be expected to do anything other than return us to "biological normality"? It is not the case, despite public-health recommendations to the contrary, that carbs are required in a healthy human diet. Most nutritionists still insist that a diet requires 120 to 130 grams of carbs/day because this is the amount of glucose that the brain and CNS will metabolize when the diet is carb-rich. But what the brain uses and what it requires are 2 different things. WIthout carbs in the diet, the brain and CNS will run on ketone bodies, converted from dietary fat and from the fatty acids released by the adipose tissue; on glycerol, also released from the fat tissue with the breakdown of triglycerides into free fatty acids; and on glucose, converted from the protein in the diet. SInce a carb-restricted diet, unrestricted by calories, will, by definition, include considerable fat and protein, there will be no shortage of fuel for the brain. Indeed, this is likely to be the fuel mixture that our brains evolved to use, and our brains seem to run more efficiently on this fuel mixture than they do on glucose alone.
For me what was so remarkable here was being walked through the science of WHY all calories aren't equal, why animals and people lay on fat even on low-calorie regimens, and a feasible hypotehsis on exactly why sugars can be addicting in the manner of alcohol and addictive drugs (they certainly are for me; moderation is entirely impossible). Taubes also makes the point, which gets lost in much of general rhetoric about fat, diets, eating, that there will always be people who will remain lean no matter what sort of diet they have, which explains why even among populations that have huge rates of obesity and type 2 diabetes due to the general diet, there are still people who are not fat and not diabetic. This is important to me, because I've often seen in the media (and in nasty comments on various blogs) and been the subject of harangues about how if some people can control their size by food restriction and exercise, so should I, if I REALLY wanted to. Taubes shows the data that demonstrates that this just isn't true, that there's no cause-and-effect.
As much as its about diet and disease, the book is also about science, and how it is practiced, and badly practiced, how politics and personalities and the separation of disciplines, among other things, can result in the establishments of erroneous dogmas. (Interestingly, one could almost blame much of the low-fat-is-good stuff on Hitler--prior to WWII much of the more in-depth and interesting nutrition research went on in Germany and was published in German; those scientists who got out and came to the US were never able to establish themselves at prestigious institutions, and anti-German bias and disinterest in work not published in English effectively sunk their research findings from the notice of the scientific community.)
Anyway, I'll stop now before I write out the entire book. I wanted to go on at some length because i know a fair few of you who are reading my jnl are interested in these matters.
A review of the book at the Chicago Sun-Times.
Taubes' NY Times article, "What If It's All A Big Fat Lie?" in which he lays out his argument.