Why Diets Are So Last Year

This January, make a resolution to not go on a diet. Research shows that it might be your best shot at weighing less in time for next New Year’s.

- Anne Marie O’Connor

Year after year, “going on a diet” and “losing weight” top the lists of the most popular New Year’s resolutions. And just as inevitably, most people have ditched the green-smoothie cleanses and carb-free meals like chicken breast and broccoli way before Super Bowl Sunday. While they may drop a few pounds, many of them will have regained the weight—and a few bonus pounds to boot—by the end of the year.

A 2016 study in Obesity that followed 14 Biggest Loser contestants identified the probable cause: Not only had 13 of them regained the weight six years after being on the show, but their metabolisms had slowed significantly, so they were burning fewer calories than before they went on the show.

The study confirmed the findings of previous research, including a 2012 study in the International Journal of Obesity that followed more than 4,000 sets of identical twins; those who had gone on a diet were more likely to be heavier than their twin who had never tried to lose weight. Researchers also discovered that women who had dieted more than twice were five times as likely to end up overweight as their twin.

WHY DIETS MAKE YOU GAIN WEIGHT

“The problem with diets in the long term is that our bodies are really good at protecting us from starving to death,” explains Traci Mann, a professor of psychology at the University of Minnesota and the author of Secrets from the Eating Lab: The Science of Weight Loss, the Myth of Willpower, and Why You Should Never Diet Again (Harper Wave, 2015). “So if not enough calories are coming in, or we’ve lost a bunch of weight, our bodies switch into starvation mode, and all these changes happen that are designed to keep us alive.”