A sobering report in the New York Times about the weight gained by contestants on "The Biggest Loser" confirms what every failed dieter knows: it is harder to keep weight off than to lose it. Research on post-dieting metabolism and eating behavior among these contestants might convince some wannabe dieters to indefinitely put off even starting a diet. The post-diet contestants were found to have such slow metabolisms that their bodies were using up far fewer calories than predicted, based on their height and weight. People of the same size who had not been on a prolonged diet were found to be using up less than 800 calories. It was no surprise that the contestants were gaining weight.
If that were not bad enough, the contestants experienced an almost constant need to overeat. The urges were strong enough to cause them to binge on foods that never should have been eaten, even in small quantities, if they were to remain thin.
These changes in metabolism and absence of self-control over eating are hardly unknown. Decades ago, scientists measured changes in calorie use before and following substantial weight loss. They put people in a room called a "respiration chamber" for 24-48 hours, and measured how many calories were used when the volunteer was in a relatively inactive state. The results were consistent with those reported for the Biggest Losers: After substantial weight loss the body uses markedly fewer calories than those of people of the same size that have not lost weight. Why this occurs is still not understood years after the first observations. Changes in the activity of certain thyroid hormones might cause a slowdown of metabolism, but other factors may also be involved which have not yet been identified. This is a significant problem since it means that at present there is no way of preventing others who endure a rapid weight loss caused, essentially, by low rations and excess exercise from suffering the same fate.
Other possible explanations for the post-diet side effect of weight gain are related to the reasons weight was added initially. Some of the contestants had been gaining weight since childhood and were unable to stop the weight gain. Why were they unable to halve their weight gain before it transformed them into morbidly obese individuals? Were they gaining weight because their bodies did not have the same control mechanisms to regulate their food intake? Were they always less active than their thinner peers? Did they drink soda instead of water, eat fried fatty food rather than lean protein and vegetables, and consume many large meals each day? Was food used to dampen emotional pain, or as entertainment?
Each of us have our own reasons for overeating, whether it is only a few extra calories, or several thousand. Not knowing why, or just as likely unable to change the "Why?" will make maintaining weight loss very difficult.
Undoing the side effect, weight gain, after successful weight loss requires:
• Decreasing post-diet hunger and lack of satiety;
• Developing strategies to halt overeating in response to emotional and situational triggers;
• Adherence to a food regimen compatible with anticipated post-diet metabolic slowing;
• Investigating whether changes in gut bacteria allow too many calories to enter the body;
• Decreasing sleep disturbances that trigger fatigue associated overeating; as well as
• Preventing overeating triggered by seasonal decrease in sunlight.
The immediate problem that requires intervention is making it possible for the ex-dieter to adhere to a reduced-calorie food plan. Unless the calories consumed correspond to those required by the now sluggish metabolism, weight will be gained again. And yet, the dieter is being asked to stay on a post-diet diet. How frustrating and difficult! After months of being caloric deprived, the dieter is being told to continue the deprivation.
Perhaps it is time to help the dieter by offering temporary treatment with an appetite-suppressing drug.
The FDA has approved several new appetite-suppressant drugs over the past three years. They all have side effects, some of which, such as elevated blood pressure or increased heart rate, might be dangerous for an obese individual who already suffers from cardiovascular problems. But if healthy, normal weight post-dieters used these drugs? Their side effects may be less potentially harmful.
These drugs decrease hunger and cravings and increase satiety. They might help the ex-dieter follow a reduced calorie regimen at least for some of the time it takes for their bodies to become metabolically normal. If they are no longer beset with the urge to overeat and the frustration of seeing their weight increase, they might have the mental and emotional energy to grapple with the triggers that caused them to become obese.
We still must figure out how to prevent the metabolic meltdown that makes it so easy to gain weight after a diet. We still must find out how to prevent post-diet weakening of the satiety signals and exacerbation of urges to binge. We still must develop counseling paradigms during and after the diet to address all the factors that caused weight to be gained. Without these answers, the dieter may not be able to escape the side effect of successful weight loss, i.e., weight regained.