The following guest post is by Dr. Michael Joyner, a medical researcher at the Mayo Clinic. These views are his own. You can follow him on Twitter @DrMJoyner.
One of the biggest health news stories last week was about the long term weight loss results reported in 14 participants from the Biggest Loser reality TV show. At the start of the show the average contestant weighed about 150 kg. After 30 weeks of extreme diet and exercise the average was about 90 kg (a weight loss of about 130 lbs). However, six years later the average weight was about 130 kg. So on average a sustained weight loss of only about 20 kg or 45 pounds was seen.
One of the reasons it is so hard to lose weight is that metabolism slows with weight loss making it hard to keep the pounds off. This point was highlighted by coverage in the New York Times and other outlets, most of which emphasized the fact that contestants regained weight.
However, one thing missing from the coverage of most media outlets is what the individual data looked like. The graph below shows just how variable the responses in the 14 subjects were. Two subjects ended up heavier after six years. Three ended up back at baseline. Eight kept about 50-80% of the weight off. One actually lost more weight.
How do these results stack up? First, the conventional wisdom is that perhaps 90% or more of dieters fail to generate a sustained weight loss of 10%. Population data is a little more optimistic suggesting that perhaps 15% of Americans have lost 10% of body weight and kept it off. So the Biggest Loser results, which show more than half of contestants keeping more than 50% of their weight off, suggest that many “Biggest Losers” are doing quite well by comparison.
Second, while diet and exercise are often compared unfavorably to gastric bypass in stories about weight loss, surgery is not a panacea. Most patients who undergo gastric bypass surgery regain weight, and some of them regain a lot of weight. In fact, if you exclude the two people who actually ended up above their baseline after six years, the Biggest Loser results look a lot like those from big long-term studies on gastric bypass patients.
This suggests that as crazy as the weight loss program from Biggest Loser TV program seems, it actually worked very well over time compared with the alternatives.
We should keep in mind, of course, that this is a tiny sample of only 14 individuals, and that their experience on the show makes them somewhat unusual in the annals of weight loss studies.
One other interesting point, as noted by Amby Burfoot in his reporting at Runner’s World, is that the people who kept the most weight off actually had the biggest drop in metabolism. (The trend line in the figure shows more percentage weight loss [horizontal axis] among those with the biggest metabolic adaptation [vertical axis].) So somehow those who achieved long term success did it in spite of the slowing of their metabolism.
Other long-term studies suggest that those who lose a lot of weight and keep it off re-engineer their lives. In almost 3000 subjects followed for ten years:
Mean weight loss was 31.3 kg at baseline, 23.8 kg at 5 years and 23.1 kg at 10 years. More than 87% of participants were estimated to be still maintaining at least a 10% weight loss at Years 5 and 10. Larger initial weight losses and longer duration of maintenance were associated with better long-term outcomes. Decreases in leisure-time physical activity, dietary restraint, and frequency of self-weighing and increases in percentage of energy intake from fat and disinhibition were associated with greater weight regain.
In other words people who lose a lot of weight and keep it off exercise almost every day, weigh themselves frequently and really watch what they eat. My guess is that these same behaviors explain why nine of fourteen biggest losers kept a lot of weight off over time.
So it seems to me that focusing mainly on the weight regain of these contestants is to miss the “news” from this study. Almost everyone who loses weight, no matter what method they use, is going to gain a lot of it back again. The Biggest Losers were more successful than most at avoiding this unfortunate outcome. A better headline, then, might have read something along the lines of, “’Biggest Loser’ results similar to weight loss surgery for many dieters.”
Michael Joyner, MD has done preclinical technical consulting for GSK, Amgen, Boston Scientific, Edwards, and Nonin on issues related to physiological monitoring, cardiovascular disease and diabetes. He is on the board of Xcede a startup focused on tissue sealants. As a clinical anesthesiologist he prescribes no drugs or products related to his consulting. You can follow him on twitter @DrMJoyner.