Jeb Bush is fantasizing about food right now. Photo: Brooks Kraft/Corbis

Jeb Bush is going to get fat again. This is a near-scientific certainty of which Bush is apparently unaware. Instead, Bush seems to believe that he has discovered a brilliant new weight-loss method, “The Paleo Diet,” which has changed his life for the better. “It’s really working,” Al Cardenas, a longtime Bush friend, tells Michael Barbaro. Spoiler: It’s not working.

Now, it is true that Bush has lost an enormous amount of weight. But there are several reasons why he is bound to gain it back. First, diets in general don’t work, which is why there are so many of them. People go on new diets constantly, the diet eventually fails, and they look for a new one. Barbaro indeed describes the many diets Bush has tried through his life, always convinced that This Time Is Different.

Second, the Paleo diet, which presumes that our bodies are designed to consume the kinds of food eaten by our hunter-gatherer ancestors, is a particularly stupid diet. It’s based on pseudoscience.

Third, Bush can’t take this very long. It is true that he has lost a lot of weight while on the Paleo diet. But he has not lost weight because of the Paleo diet. He has lost weight because he is starving himself. “I am always hungry,” Bush tells Barbaro. Right, a diet based on being hungry all the time can work for a limited period of time, but eventually, you will give it up. You can lose weight by changing your diet and exercise habits in a way that does not subject you to constant deprivation. But Bush’s plan to stay thin for the long-term by staying on the Paleo diet has exactly the same prospects for success as balancing the budget and cutting taxes: zero.