MOST OF US know the occasional cheat meal is no big deal. It’s not like one night of overeating can undo months of dieting and working out. But what about a week of overeating? Or what if eating till your stomach hurts becomes a regular weekend habit? If your diet is clean all week, can overdoing it actually mess with your body?
The answer is yes, says Ilyse Schapiro, R.D., C.D.N.: “If you’re healthy, occasionally overeating won’t kill you. But regularly overeating, or overeating for an extended period—such as a week or more—may cause changes in health and body composition.”
Kind of scary, right? Here’s everything you need to know before going on that next burger bender—and how to indulge without throwing your health goals or physique progress off track.
1. Overeating can soften your six-pack
If you’re healthy, overeating on Thanksgiving or over a holiday weekend probably won’t fill out your washboard abs. But it really depends on how much you eat. Whether you overeat for one day or one week, your body will transform any extra calories into fat, says Leah Kaufman, R.D. “If you consume an excess of 3,500 calories, you’ll gain a pound of fat. If you consume 7,000 excess calories, you’ll gain two pounds of fat, and so on.”
2. Overeating nudges you closer to diabetes
The extra body fat that comes about as a result of overeating does more than just make your pants feel tight. It can also lead to insulin resistance, a precursor to diabetes that occurs when cells are unable to convert blood glucose into energy. And we’re not talking about months or years down the line, either. You can become insulin-resistant in a matter of days. In one Science Translational Medicine study, six healthy men ate 6,000 calories per day and stayed on bed rest for seven days. After just two days of extreme binge eating, all of the study participants had developed insulin resistance. Though the researchers hypothesized the men’s blood sugar issues would resolve after they returned to their regular diets and fitness routines, they argued that if the men were to continue to eat in excess, they would develop full-blown diabetes.
3. Overeating can mess with that “full” feeling
If overeating becomes your new normal and you start to gain weight, levels of your weight-regulating hormones may become altered. In one Nutrition and Diabetes study, researchers overfed mice and found that their intestines stopped producing uroguanylin, a hormone that helps send feelings of fullness to the brain. When the animals started to consume a healthy number of calories again, levels of uroguanylin increased. Experts hypothesize that the same thing happens to humans, as well.
“After a period of overeating, one’s perception of fullness may be altered,” explains Schapiro, who was not involved with the study. “After the body becomes accustomed to eating more calories, taking in fewer calories will confuse the body and make it think that it’s underfed, causing hunger to persist.”