It's NBC's Monday night television juggernaut and the guilty pleasure of over 7 million viewers. Now in its 14th season, The Biggest Loser is a an industry unto itself, with a 2009 estimate by the New York Times pegging its worth at $100 million in annual revenue.
Consequent perhaps to the show's immense popularity and polarizing approach, The Biggest Loser has led to the publication of a number of peer-reviewed medical studies that look at its impact on both the participants and the viewers. Their results are anything but pretty.
Two studies have been conducted that examine how watching The Biggest Loser affects viewers' attitudes towards those with obesity. Perhaps not surprisingly, given the apparent tenor of the show—that obesity is a consequence of personal laziness and gluttony—the first study, published in the journal Obesity, showed that watching even a single episode of The Biggest Loser led viewers to dramatically increase their own hateful and negative biases towards those with obesity.
This result may be explicable on the basis of the second study, published in the journal Health Communication, which found that watching The Biggest Loser led viewers to be much more likely to believe that weight is well within an individual's locus of personal control. And, of course, that message echoes the show's—that if you just want it badly enough, you can make it happen.The corollary is that if you don't make it happen, you must simply be lazy, which in turn may explain the increase seen in viewers' weight biases.
Interestingly, those same viewers who, consequent to the show, might attribute being overweight to laziness, were reported to be less inclined (go figure) to want to exercise or expect it to be enjoyable after watching a 7.5 minute workout on the show, according to a study published this month in the American Journal of Health Behavior. "People are screaming and crying and throwing up, and if you’re not a regular exerciser you might think this is what exercise is—that it’s this horrible experience where you have to push yourself to the extremes and the limits, which is completely wrong," said the study's lead author Tanya Berry of the University of Alberta.
And what of the participants? Will being on The Biggest Loser change their lives forever? According to a paper published in the Journal of Clinical Endocrinology and Metabolism, the answer is yes, but perhaps for the worse. The researchers, including the show's own Robert Huizenga, looked at the metabolisms of participants following the completion of their first seven months with The Biggest Loser. As expected, due to weight loss and an effect broadly referred to as "metabolic adaptation," the participants' burned fewer calories at rest following their massive weight losses.
What wasn't expected was the the magnitude of that decrease; researchers found that participants metabolisms slowed by an average of 504 more calories than would have been expected simply as a consequence of losing weight. In other words, participants' metabolisms slowed down to a much greater degree than was predicted. In turn, this suggests that the show's approach to weight loss may have risks unto itself and led the researchers to state: "Unfortunately, fat free mass preservation did not prevent the slowing of metabolic rate during active weight loss, which may predispose to weight regain unless the participants maintain high levels of physical activity or significant caloric restriction."
This may explain why, when I interviewed three alumni of the TV show, they reported that 85 to 90 percent of participants regain most, if not all, of the weight that they lose, and that those who keep it off are generally the participants who have turned their losses into careers as personal trainers or motivational speakers.
Ultimately the current state of the evidence on the phenomenon known as The Biggest Loser is far from flattering. It suggests that the show may be detrimental to both viewers and participants in that its combination of derision, personal blame, and extremes of exercise and dieting fuel societal weight bias while simultaneously discouraging people from exercising. Meanwhile, for participants, it seems to disproportionately slow down their metabolisms to the point where they're burning a full meal fewer calories than would be expected by their losses.
If you're a regular viewer here's my suggestion. Instead of spending two hours a week watching The Biggest Loser, why not use that same amount of time to ensure you pack your lunch for work each and every day and take three 20-minute walks a week with a friend or a loved one. No doubt the impact of those behaviors will be far more valuable and positive to your mental and physical well-being than watching a show that science suggests may be doing more harm than good.
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Yoni Freedhoff, MD, is an assistant professor of family medicine at the University of Ottawa, where he's the founder and medical director of the Bariatric Medical Institute—dedicated to non-surgical weight management since 2004. Dr. Freedhoff sounds off daily on his award-winning blog, Weighty Matters, and is also easily reachable on Twitter. Dr. Freedhoff's latest book Why Diets Fail and How to Make Yours Work will be published by Random House’s Crown/Harmony in 2014.