It’s an unfortunate fact that most people who lose a significant amount of weight gain a significant amount of it back over time. Statistics show that up to 90% of people who lose weight regain it back within 5 years. Why is weight maintenance so difficult?
There’s a theory that you have a genetically pre-determined set point, a weight at which your body tries to maintain. When you deviate too far from this set point, your body sabotages your weight loss attempt by boosting your appetite and decreasing your activity level. A recent study published in the New England Journal of Medicine seems to confirm this idea.
Researchers in Australia recruited 50 obese and overweight people to participate in a calorie-restricted diet and exercise program to lose weight. Over the course of the 10-week program, the participants lost an average of 14% of their body weight. Unfortunately, when they followed up with the “successful losers” 62 weeks later, they had regained almost half of the weight they had lost.
During the course of the study, they measured levels of hormones that control appetite including leptin, ghrelin, CCK, GIP, insulin and peptide YY. Weight loss caused levels of hormones like leptin that suppress appetite to drop and ghrelin levels to rise. Ghrelin is a hormone produced by cells that line the stomach that increases the desire to eat. It’s ghrelin that gives you that rumbly feeling in your stomach when you’ve gone too long without eating. In addition, the participants reported feeling hungry much of the time. This isn’t surprising since their ghrelin levels were still elevated.
What Does This Mean?
When you lose weight, leptin levels typically fall since it’s produced by fat cells. When energy stores are high, more leptin is produced, which causes appetite suppression. As energy levels decline through calorie restriction or weight loss, leptin levels go up, which stimulates appetite. Ghrelin levels increase with energy restriction, which motivates you to eat. This study suggests that these hormonal changes persist a year or longer after losing weight, so people who successfully lose are fighting a battle with their appetite hormones. For many people, that’s an easy battle to lose. Hunger is a strong motivator and one that’s difficult to ignore.
Is Weight Maintenance Impossible?
Fighting your appetite hormones can be a challenge, but exercise, especially strength training and high-intensity exercise, may tilt the scale in your favor. Higher intensity exercise has an appetite suppressive effect for many people, and strength training builds lean body mass, which boosts metabolism. Many people also let their guard down after losing weight and gradually fall back into their old habits. One way to prevent this is to weigh twice a week and make adjustments based on what the scale shows. It’s easy for two pounds of weight gain to turn into four when you don’t adjust your diet. It’s also a good idea to keep a food diary to make sure you’re staying on track.
Aetna InteliHealth. “Stopping that Rebound in Weight”
N Engl J Med 2012; 366:380-382.