For decades we have been taught that fat is bad for us, carbohydrates better, and that the key to a healthy weight is eating less and exercising more. Yet with more and more people acting on this advice, we have seen unprecedented epidemics of obesity and diabetes. Taubes argues persuasively that the problem lies in refined carbohydrates (white flour, sugar, easily digested starches)—via their dramatic effect on insulin, the hormone that regulates fat accumulation—and that the key to good health is the kind of calories we take in, not the number. There are good calories, and bad ones.

Taubes traces how the common assumption that carbohydrates are fattening was abandoned in the 1960s when fat and cholesterol were blamed for heart disease and then —wrongly—were seen as the causes of a host of other maladies, including cancer. He shows us how these unproven hypotheses were emphatically embraced by authorities in nutrition, public health, and clinical medicine, in spite of how well-conceived clinical trials have consistently refuted them. He also documents the dietary trials of carbohydrate-restriction, which consistently show that the fewer carbohydrates we consume, the leaner we will be.

With precise references to the most significant existing clinical studies, he convinces us that there is no compelling scientific evidence demonstrating that saturated fat and cholesterol cause heart disease, that salt causes high blood pressure, and that fiber is a necessary part of a healthy diet. Based on the evidence that does exist, he leads us to conclude that the only healthy way to lose weight and remain lean is to eat fewer carbohydrates or to change the type of the carbohydrates we do eat, and, for some of us, perhaps to eat virtually none at all.

Good Calories, Bad Calories is a tour de force of scientific investigation—certain to redefine the ongoing debate about the foods we eat and their effects on our health.