Regaining Lost Weight? Your Hormones May Be the Culprit

Is your biology conspiring to keep you heavy?


If you're one of the many people struggling to maintain your weight loss after dieting, emerging research may help you understand your plight. A recent study published in the New England Journal of Medicine found that dieters who regain weight are not simply backsliding into old eating habits: They're battling biology itself, which tends to fight to keep weight on.

While more research is needed before we can make firm conclusions, it seems the hormones that kick in once you've lost weight both slow your metabolism—and make you feel hungrier than before. In the study, one hormone, leptin, dropped as soon as the subjects lost weight .When leptin falls, hunger swells and metabolism stalls.The combination of increasing appetite and slowing metabolism is a double whammy for people looking to keep weight off. After a year, leptin levels were still lower than they were when the study began, only increasing as subjects got heavier. Worse, a year out, other hunger-provoking hormones, such as ghrelin, were altered in ways that left participants with bigger appetites than at the study's start.

Why in the world would your body want to keep you heavy? Perhaps because being too thin was once a disadvantage that threatened the survival and reproductive abilities of our ancestors, researchers speculate. Disheartening? Yes, but at least you can stop beating yourself up if you're having trouble keeping off lost pounds—despite your hard work. Your hormones could be sabotaging your efforts.

The study reaffirms what we already know: that it's harder to lose weight than to not gain in the first place. But that's useless advice for anyone with a weight problem. Although researchers will be investigating whether restoring hormones to normal levels after weight loss could help legions of frustrated dieters, it's too soon to tell.

What's a dieter to do?

The good news: Weight-loss success stories abound. Many people do manage to lose weight and keep it off for good. For proof, look no further than the National Weight Control Registry, a study of thousands of adults who've done just that. With hard work and dedication, you too can reach a healthy—and sustainable—weight. One way to combat weight regain is to keep your metabolism from dipping. The metabolic process determines the clip at which calories are burned, and somewhat affects the ease with which we pack on or shed pounds. The following strategies can help. Take that, hormones!

Try interval training. High-intensity interval-type training has been shown to raise metabolism longer and higher than lower-intensity exercise. If you aren't working up a sweat during your workouts, it's probably not hard enough.*

Drink water throughout the day. Research suggests that dehydration can sap your metabolic rate by 2 percent. Staying hydrated is an easy way to help boost overall metabolic rate. Every day, you should aim to consume at least half of your body weight in fluid ounces of H20.

Enjoy some caffeine. It boosts your metabolic rate for up to three hours after you imbibe.

*Always check with your physician before beginning any new exercise regimen.

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Katherine Brooking, MS, RD, is a registered dietitian with a master's degree in nutrition education from Columbia University. She is a frequent nutrition contributor to top-tier national morning shows including the Today show, Live with Regis and Kelly, The Early Show on CBS, Good Morning America Health, as well as dozens of local affiliate stations across the country. Please visit her blog at