This is not a diet book, per se. But, it builds upon Taubes's first book on the subject, "Good Calories, Bad Calories" by making the case for years of nutrition science and medical advice being simply wrong and likely to blame for the current obesity epidemic.

What he's saying is not really new, if you buy into low-carb diets. Taubes is challenging the belief that still persists today that fat makes you fat. Taubes asserts that dietary fats saturated or not are not making us fat, and not giving us heart disease. This remains highly controversial as it flies in the face of some significant medical studies. Taubes believes the data from these medical studies was misinterpreted.

Michael Pollan (author of The Omnivore's Dilemma) supports Taubes argument that carbs and processed foods are likely the cause of the obesity epidemic and other health issues like diabetes.

Taubes has gotten a lot of criticism since "Good Calories, Bad Calories" came out. Why We Get Fat is in part a response to that criticism, further making his point and exposing many old beliefs related to diet and nutrition. For example, he also challenges calorie counting as being a poor measure because the systems in our body that manage things like insulin regulation are simply more complicated than that. What you eats matters and how your body processes the foods makes a huge difference.

While much of the book focused on explaining and reinterpreting or exposing past research and beliefs, the final chapters do outline a fairly simple and easy to follow diet. This diet is not so unlike modern low-carb diets. It is not a low-fat diet and not a calorie-counting diet.