by Gary Taubes
(Knopf, $27.95)

Americans need to rethink most of what they’ve been taught about diet and exercise, says science journalist Gary Taubes. Despite what the government has been saying for the past 40 or 50 years, cutting fat from your diet won’t help you shed pounds or extend your life expectancy. Exercising won’t burn off those love handles, either. The best evidence available today indicates that public health officials bought into some flimsy hypotheses in the 1960s and have been mindlessly repeating them ever since. If we really want to know why Americans are overweight, Taubes says, scientists need to be willing to consider that future generations could be better off saying yes to butter and bacon and no to Stairmasters and bread.

It’s “bizarre” how bad some expert advice on diet is, said John Tierney in The New York Times. When surgeon general C. Everett Koop labeled ice cream a health menace equivalent to tobacco some 20 years ago, he unwittingly revealed himself to be a victim of what social scientists call an “informational cascade.” As Taubes shows, the whole “fat is bad” theory started with a 1953 heart-disease study whose findings should have helped clear fat of blame. Instead, a single prominent researcher championed the opposite conclusion and started a groundswell. Soon, almost every nutritionist in the country believed it. Taubes is certainly brave to stand up to conventional wisdom, said Gina Kolata, also in the Times. It’s just not clear that his own theory about weight gain provides a better answer.

Taubes suspects that refined carbohydrates are the real killers at the dinner table, said Scott Gottlieb in The Wall Street Journal. Refined carbs—particularly sugars and sweeteners—trigger dramatic surges in insulin, the hormone that governs fat accumulation. Though Taubes cares too much about good science to suggest that he’s positively identified the culprit behind recent rises in obesity, diabetes, and heart disease, he makes “a fascinating case.” Consider just this one fact from a book that’s almost overloaded with them, said Tony Miksanek in the Chicago Sun-Times. The typical American of the early 1800s ate 178 pounds of meat each year. Today, meat consumption is about the same, but the average American has tacked on nearly 150 pounds of sugars and sweeteners.