Why We Get Fat: And What to Do About It Paperback – December 27, 2011

I've read quite a few books that make some of the same points this one does about nutrition. I was already convinced saturated fat wasn't bad, and didn't cause heart disease. I was already convinced that sugar wasn't good for you--nor was a lot of bread and pasta. BUT I had never questioned the calories in/calories out theory. I knew plenty of people carrying extra pounds who exercised a lot and who didn't appear to eat any worse than I did (as a thin person), but I figured they must. I never questioned to think WHY do people eat more than need. The short answer is: glucose drives insulin drives fat. Taubes states that this is inarguable. I thought, well if it is inarguable than if I go read this Biochemistry, Fifth Edition: International Version (hardcover) book sitting on my bookshelf it will say the same thing. Sure enough it did, granted using a lot bigger words than Taubes does. Fatty acids will not be released into the blood stream to be used as energy if the glucose level is high. Thus it is logical to conclude that if you eat a diet that causes your blood sugar to frequently be high, all energy you consume that is not immediately needed will be stored in your fat cells and will not be released. You will not get to use all of the 800 calories you eat at one meal, only the 100 or so you need immediately, and thus you will soon be hungry again, and will overeat. And in contrast if your blood sugar is stable and you can access that stored energy you will not be hungry and won't overeat. Also it doesn't matter if you are eating fat or glucose your body will convert what its got to what it needs.

Another controversial claim he is that exercise does not help people lose weight permanently. I am a champion of exercise. How could this be? Honestly his arguments made sense, kind of, but didn't completely convince me. However when I pulled out the Biochem book it says, "Muscle retains glucose, its preferred fuel for bursts of activity...In resting muscle, fatty acids are the major fuel, meeting 85 percent of the energy needs." So there you go. If you are trying to lose weight, and are doing so by keeping your blood sugar stable, which is releasing fatty acids into your blood stream, and you want those fatty acids to be used, versus having your body (ie muscles) crave glucose, then intense exercise will not help you. Your body will more readily use those fatty acids if it is resting.

The other question is whether ketosis is a desirable state to be in. There is a bit of controversy on this and I haven't resolved an opinion one way or the other. I have epilepsy and know that a ketogenic diet is a viable treatment for epilepsy. I know that there are some societies, particularly the Inuits, that ate a mostly ketogenic diet, so it is not unheard of. Maybe humans are supposed to enter ketosis seasonally? Your brain and muscles do like glucose--can they run as well on a ketogenic diet? Some say they can, it just takes an adjustment period. Either way, I definitely think for a person who has excess weight Atkins is vindicated. Cut your carbs, drop significant amounts of weight (probably feeling crappy in the transition, but resting muscles can use the fuel better anyway so crashing on the couch is fine till you get used to it and end up having more energy than before). When you hit a desirable weight slowly add back a small amount of carbs until you start gaining again, and start an exercise routine with all your new found energy. As exercise is good for weight maintenance, and it's good for you brain (read Spark: The Revolutionary New Science of Exercise and the Brain by John Ratey). Then do that forever. I would really love to see a long term study where the participants stay on the diet.

I found the book very readable and engaging. How much fruit is too much? Will eating more fat really improve your cholesterol profile? How many carbs are too many? I don't know. Taubes makes some guesses, but nutrition is a very complex science that I don't think anyone completely understands. If you read vegan arguments they make many of the same claims that Taubes does (better cholesterol levels, weight management, etc). However it does seem that every major nutritional philosophy pegs sugar as being a major problem. It may be as simple as that. I'll process this information. Read Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health (Vintage). Experiment on myself (finger pokes here I come), and have increased anxiety about what I feed my kids--especially the pasta, bread, fruit and sugar loving one.

(*I edited this section after my initial review.)

The brilliant thing about science is that when something is disproved once, it's disproved forever. The not-so-brilliant thing about public health policy is that it has little to do with science.

Everyone in the developed world knows what's causing our obesity epidemic. BBC nailed it: "We eat too much, and too much of the wrong things," and Michelle Obama tells us "We have to move more." Clearly what we need is a balanced diet of lean meats, some good fats, and complex carbohydrates like fruit, vegetables and whole grain bread, and exercise of 30 to 90 minutes per day. Their prescription is completely reasonable and makes intuitive sense.

It is neat, plausible, and wrong. It has in fact been disproved, as nearly as "disproof" can exist in nutrition science.

In his previous book, Good Calories Bad Calories, respected science journalist Gary Taubes exhaustively researched and cited two centuries worth of research in nutrition. He came to the conclusion that none of those recommendations is supported by science, because the fundamental theory on which they're based is wrong. Why We Get Fat is an updated summary of that earlier work, much quicker and easier to read, with some significant points clarified.

The most important point of the book is that all those public recommendations -- the food pyramid, the "eat food, not too much" approach, everything we know about a balanced lifestyle -- is founded on the premise of Calories In vs. Calories Out. That we get fat because we eat too many calories, or we don't burn enough of them through movement. But this is nonsense. It's not just wrong, it is actually not a statement about what causes obesity at all (or heart disease, cancer or diabetes, for that matter.) It is, in Taubes' words, a "junior high level mistake," because it tells us nothing about fat accumulation. If we get fat, by definition we have taken in more calories than we've put out -- but WHY we took in those calories, or didn't burn them, is the key point.

Taubes reviews the scientific literature (rather than the popular press) and presents a conclusion that was common knowledge before WWII, and heresy afterward: we get fat because our fat cells have become disregulated and are taking nutrients that should be available to other tissues. Like a tumor, the cells live for themselves rather than in balance with the rest of the body. And since those nutrients aren't available, we become hungry and tired. Therefore we eat more, and move less.

For the chronic dieters among us, one passage about animal models will explain decades of frustration. Rodents with a particular part of the hypothalamus destroyed would become obese and/or sedentary *as a consequence* of their bodies putting on more fat. "After the surgery, their fat tissue sucks up calories to make more fat; this leaves insufficient fuel for the rest of the body...The only way to prevent these animals from getting obese is to starve them...they get fat not by overeating but by eating at all." Sound familiar?

The problem isn't one of gluttony and sloth, as Taubes refers to it, but of hormone balance. Simply put, some people are more sensitive to the hormone effects of insulin, cortisol, and a few other -ols, than other people are. The more sensitive you are, the more you're likely to get fat, and the more fat you're likely to get, in the presence of even small amounts of carbohydrate -- and in the absence of enough fat.

That's right, this book advocates eating fat. Not just moderately, but as much fat as possible, up to 78% of calories. Not lean meats, not Jenny-O 99.6% fat-free turkey, not skinless chicken breasts, but lard. Yes, lard. The healthy way of eating, according to Taubes, is moderately high protein and high fat. Yes, high fat. About a 3:1 ratio of fat to protein, and almost no carbohydrates. (Telling people to eat a balanced diet containing carbohydrates is, he says, equivalent to telling smokers to include a balanced serving of cigarettes.) And he demonstrates exactly why a high-fat, low-carbohydrate diet is the most heart-healthy approach, as borne out by several dozen recent studies.

While Taubes acknowledges that exercise seems to be good for us for a variety of reasons, weight control isn't one of them. Study after study conducted by proponents of exercise have admitted that they see no compelling evidence for exercise as a weight-loss tool. And it makes sense if you throw out the calories in/calories out model of why we get fat. If we're fat because our fat tissues are starving the rest of our cells of fuel, exercise is just going to make us hungrier and more tired, not leaner and more fit. (It's worth noting that according to Taubes, in the 1930s obese patients were treated with bed rest.)

[This review was edited to clarify the following point.] The main thrust of Taubes' argument, however, surrounds sugar and to a lesser extent any carbohydrate. Insulin is the primary hormone that fixes fat in the fat cells. This is why Type I diabetics lose weight: they're not producing enough insulin. Since insulin is manufactured in direct response to carbohydrates, if you don't eat them, you won't have a mechanism by which to store fat. (Taubes notes that this mechanism is not controversial; it simply hasn't had an impact on nutrition policy.) Taubes argues that any success in standard diets can be attributed directly to the dieter's reduced intake of carbohydrates, especially sugars and particularly fructose.

Once the underlying cause of obesity is understood (hormone balance, not gluttony/sloth) the recommendations on what to do about it are surprisingly simple and therefore brief. This is a book about the science of nutrition, not a diet book, but there is a list of recommended foods in the Appendix. The book does not tell you how to eat in a restaurant. But it does tell you that the issue isn't in your brain, your willpower, your character, your job, your environment or even (except to the extent that you're sensitive to carbohydrate) in your genes. The problem with fat is in your fat cells.

For a lay audience, this book is as good as it gets if you want to read actual science about health and nutrition. If you're of scientific or technical bent, read Good Calories Bad Calories first, then give Why We Get Fat to your parents.