EVERYTHING YOU KNOW ABOUT DIET IS WRONG

Despite a proliferation of diets supposedly based on science, most theories about what to eat and why are flawed

- DAVID H. FREEDMAN

THE ARTIFICIAL SWEETENER ASPARtame is found in most diet sodas and more than 6,000 other food products consumed by hundreds of millions of people around the world. So on July 14 when a group working under the auspices of the World Health Organization warned that the sweetener "possibly" causes cancer and that "high consumers" of aspartame-sweetened products were at risk, the news went viral. So did pronouncements a few days later that aspartame was, in fact, pretty safe. "The WHO announcement doesn't mean aspartame is linked to cancer," an official from the U.S. Food and Drug Administration told NPR, and a second committee of the WHO agreed.

Confused yet?

Public health messaging is often a difficult tightrope walk (see: COVID-19) and that is especially true for anything related to food-a matter of profound importance and intense public interest, about which science can't seem to make up its mind. Nutrition scientists and other food-and-health experts have for years been feeding the public conflicting and muddled advice about food, diet and health. Is it a good idea to count calories, avoid carbs, load up on meat? Is it best to eat only natural foods, avoid gluten, go vegan? Science can't provide definitive answers.

It's no wonder, then, that the diet industry is a mess of competing and contradictory claims, including the recent wave of seemingly magical cures and miracle regimens. Diets that emphasize intermittent fasting, nurturing good gut bacteria and cutting out carbs have surged in popularity, but their basis in science is sketchy. The arrival of a new generation of astonishingly effective weightloss drugs offers the tantalizing prospect of blunting America's obesity problem. But it's not clear if a lifetime drug regime will be safe or affordable for the 42 percent of Americans who are obese.