What the Media Says
It's a known fact in the diet industry that most diets fail, but many companies are now banking on the idea that personalized genetics could change that. In April, Lean Cuisine introduced a new diet plan, called Nutria, that involves a self-administered DNA test. The frozen-food company is now touting its ability to use genetic markers to help determine a consumer's "customized nutrient intake." (Still no word on when they'll bother to make the meals taste good.) Most reviews of the program focused on its unfortunate name—nutria is also the name of a giant South American rodent that's invasive in the United States—but other DNA diets have gained credulous media attention in places like the Washington Post and NPR in recent years.
What the Science Says
The idea is not completely far-fetched: Research indicates that individuals are more likely to stick with personalized nutrition advice based on factors like current diet or genotype than general advice. Beyond behavior, people do seem to process macronutrients like carbohydrates differently; a 2015 study in Cell, for example, found that post-meal blood-glucose levels varied drastically in a group of 800 people who had eaten the same food. When it comes to weight loss, individuals adhering to the same diet plan experience variable rates of success in many diet studies, leading researchers to wonder if genetics might play a role.
So Will It Work?
So far, attempts to optimize our diets based on our DNA have not panned out. A 2017 study, for example, set out to determine whether or not adhering to one's dietary genotype would improve weight loss. Over 12 months, participants followed either a low-fat or a low-carbohydrate diet, and attended 22 hour-long nutrition classes. Most participants lost weight, even individuals whose diet didn't match their dietary genotype. So test your DNA if you'd like, but attending some nutrition classes or being more mindful of the food on your plate is likely still a more effective weight-loss strategy.
A version of this story originally appeared in the September/October 2018 issue of Pacific Standard. Subscribe now to support independent journalism in the public interest. It was first published online on September 6th, 2018, exclusively for PS Premium members.