THE ARTIFICIAL SWEETENER ASPAR-tame 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 weight-loss 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.
“It’s very hard for consumers to find consistent dietary advice,” says Regan Bailey, a professor of nutrition at Texas A&M University, where she is associate director of precision nutrition for the Institute for Advancing Health Through Agriculture. “For every study that finds a particular approach works, another one comes out that’s against it.”
Getting to the bottom of diet science won’t be easy. Part of the problem is that research on food is terrifically challenging. To do it right requires tracking what people eat over long periods of time, which is expensive, and keeping them on diet plans that they may not like, which is as easy as herding cats. Because health problems tend to emerge over many years from complex causes, it’s difficult to trace them directly to diet alone, never mind particular foods or individual ingredients.
That’s why so many theories abound that may not have a sound scientific basis. What’s needed more than new theories are practical solutions grounded in the relatively small universe of unimpeachable facts about how to eat healthfully. That’s true in the realm of public policy, where a movement is afoot to protect children from the ravages of the food industry. In July, for instance, the WHO called for countries around the world to implement regulations with a particular eye
