Is Yo-Yo Dieting Really that Bad for You?
If you're looking to shed a few pounds fast, you may be tempted to try a juice fast or another trendy crash diet, but new science shows how that will only set you up for failure down the line.
iStock/preto_perolaWith holiday parties and New Year’s quickly approaching, it’s not unusual to want to drop a few pounds fast. So you cut back your calories for a few weeks, and voila, you hit your weight goals. If it sounds too good to be true, that’s because it probably is.
According to a new study published in the journal Evolution, Medicine, and Public Health, erratic eating patterns—known in the weight-loss industry as yo-yo dieting—could lead to greater weight gain once you return to your normal menu. That’s because from an evolutionary perspective, your body reads an extreme diet as a food shortage. “Frequent food shortages ‘teach’ the unconscious brain that the food supply is unreliable,” explains Andrew Higginson, PhD, senior lecturer in psychology at the University of Exeter and the study’s co-author. “Its response is to store more fat as insurance against future shortages.”
In short, when you diet like crazy—swearing off carbs or slashing your calorie budget to smithereens, you trick your body into believing that food is scarce, so when you inevitably break your diet, your body will stockpile fat to get ready for the next food shortage. In evolutionary terms, this would have been extremely useful, even lifesaving. To the modern dieter, though, it’s a major disadvantage.
The result is that you curiously begin to pack back on the pounds immediately after a bout of hardcore dieting. Dr. Higginson and his team believe that this model could explain the phenomenon of weight gain among frequent yo-yo dieters.
Here’s why this is a controversial finding: In the past, medical experts have claimed that any time spent being slimmer is healthy, regardless of how you achieve these results. Dr. Higginson doesn’t refute that claim, but he’s quick to warn of the possible dangers should yo-yo dieting lead to too much weight gain. “Whether fad dieting is good for you depends on the balance of health risks,” he explains. “If yo-yo dieting means being overweight in the long term, then it will be bad for you.” These bizarre weight-loss tricks actually help you slim down.