The Annoying Truth About Holiday Weight Gain

Holidays have a way of making you see optimism everywhere you look, including on your plate. Gingerbread cookies include ginger, which basically renders them health food. Eggnog? No problem: you read somewhere that eggs are pretty much the world’s most perfect food.

Before you know it, you’ve excused away weeks of unhealthy eating. Trouble is, the extra weight you might have noticed isn’t going anywhere.

Holiday weight gain is a well-studied phenomenon, and researchers have found that people gain about a pound from November to January. That might not sound like much, and it certainly is less than people think they gain (about 5 pounds). But that extra pound lingers. In the same study, researchers found that people don’t tend to shed that winter weight by the next year. After a few sugary Christmas seasons (plus the year’s other indulgent holidays, birthdays and anniversaries), those pounds add up.

Unfortunately, that’s a problem for many Americans. About 70% of U.S. adults are overweight or obese, and gaining weight in adulthood is a risk factor for all kinds of bad outcomes, including type-2 diabetes and cardiovascular disease. Once it’s on, losing weight can be incredibly challenging. New evidence suggests that once you gain weight, your body will work against you to keep it there. And in scientific weight loss studies, only about 25% are successful at keeping the weight off long term, says Jennifer Kuk, associate professor at York University’s School of Kinesiology and Health.

Even exercise—for all of its health merits—is not an effective way to drop weight, and may even add to weight gain through new muscle mass or a revved-up appetite.

Kuk’s research has shown that weight loss can be more complicated than the typical recommendation: “eat less, exercise more.” In her recent study, she and her team found that even if a person in today’s age exercised and ate the same amount as a person in 1988, they’d still be heavier. The researchers don’t know exactly why yet, but suspect that several factors—including pesticides, pollutants, medications, erratic eating schedules and changes in the gut microbiome—may somehow be altering human metabolism.

The best advice, of course, is to try to avoid holiday weight gain in the first place. “The less one gains, the less one then has to worry about trying to lose it,” write the authors of new research on the topic in September’s New England Journal of Medicine. But when you can’t resist indulging: