The New York Times printed an article in May of this year highlighting the surprising outcomes of several people that lost a significant amount of weight on NBC’s reality TV show “The Biggest Loser”. Many of these contestants lost well over 100 pounds, with Season 8’s winner, Danny Cahill, shedding 239 pounds in 7 months. A pretty astonishing feat to say the least.
Kevin Hall, a scientist at a federal research center followed contestants for 6 years to measure what had happened after losing this mega amount of weight and whether they kept it off. What he found was that this show and all the “winners’ were entering a new world of research that had not been embarked on yet, and that they were the guinea pigs.
To understand what happened lets dig into a little metabolic science…
Thousands of years ago, our ancestors were not able to have the abundant food supply that we have now and often found themselves hungry. Evolution selected a trait to help our ancestors’ survival: When substantial weight was lost, the resting metabolic rate (RMR) would fall.. we burn fewer calories which prevented people from losing more weight and wasting away. When famine was restored and more food was found, weight would increase and so would the resting metabolic rate. That makes sense!
What doesn’t make sense (and what bewildered these scientists) is that after intense weight loss through exercise and diet, the resting metabolic weight also fell after weight loss, but as they regained some of their weight back, their mean RMR instead of increasing, actually declined even further. There was a failure of the RMR to rise along with an increase in body weight. So their metabolisms never recovered, which was apparently a failure of re-adaptation. This problem makes gaining weight easier and losing weight harder. It’s as though their bodies were doing everything it could to get the contestants back to their original weight.
An example with one of the contestants is that as this contestant regained 100 pounds, his metabolism slowed down so much that he had to eat 800 calories less per day to just maintain his current weight….Ahhhh!!
Having a slower metabolism was not the only reason the contestants regained weight. Researchers also found a plummeting level of a hormone known as Leptin. Leptin is just one of many hormones that control hunger. The contestants started out with normal levels but by the season’s finale, had almost no Leptin at all. This left them feeling constantly hungry, having cravings and often binging. As the weight increased so did their Leptin levels, but only to about 50% to what they were when the season started. With both a lowered RMR and low Leptin levels occurring after weight loss, it’s as though their bodies just wanted to get back to their original weight. How frustrating and exhausting! According to Dr. Michael Rosenbaum, an obesity researcher at Columbia University, “The difficulty in keeping weight off reflects biology, not a pathological lack of willpower affecting two-thirds of the U.S.A.”
So what to do?
First, even though there are medications that can raise RMR and suppress hunger…they are not safe with long-term use. Research is needed in this area to help those people in this metabolic conundrum.
Second, there are some people that can maintain weight loss by restricting calories and exercise in which their biology ignores these metabolic signals.
Third, many of the contestants did not have the enormous amount of ongoing support with exercise doctors, psychologists, sleep specialists, and trainers after they went home. The more support (people to exercise with, help with healthy meals, etc), the better the long-term outcome.
What obesity research has consistently shown is that people that lose weight are at the mercy of their own bodies. This involves several hormones (which change as we age and with fluctuating weight loss and weight gain) and an altered metabolic rate that wants to desperately pull people back to their “old” weights whether it’s hundreds of pounds or that extra 10-15 pounds that dieters want to lose. Considering the high rate of obesity in this country and its associated health care costs, more research is continuing to be done to find ways to repair these mechanisms and give those hope who are trying to attain a healthy weight.
Reference- Fothergill E et al. Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity (Silver Spring) 2016 may 2; [e-pub].