Why is it so hard to lose weight?
Anyone who has seen the reality show The Biggest Loser knows that it offers a cash prize to the contestant who manages to lose the highest percentage of weight over the course of a season. Along with controversy over the various weight loss methods used on the show, including diet pills, unhealthy diets, and aggressive exercise regimens, there was also the simple fact that this approach doesn't seem to work very well. Not only have studies shown that contestants often gain back the weight they lost, but some gain even more weight afterward.
Even for contestants who did manage to lose weight, their metabolisms rarely followed suit. As a result, permanent weight loss becomes virtually impossible. According to one New York Times report describing one of these studies, "What shocked the researchers was what happened next: As the years went by and the numbers on the scale climbed, the contestants’ metabolisms did not recover... It was as if their bodies were intensifying their effort to pull the contestants back to their original weight."
Even for people losing weight using medically approved diets and exercise programs, research into their long-term success has rarely been positive. For that matter, schools and workplace settings, often alarmed by reports of an "obesity epidemic," frequently implement programs aimed at getting children and employees to lose weight, usually through such strategies as encouraging better nutrition and more exercise. Unfortunately, such programs aren't effective and accomplish little more than stigmatizing the obese even more than they already are.
As for the multibillion-dollar diet and fitness industry, its overall track record is little better. According to a 2005 overview of research into the effectiveness of commercial programs, only a few studies are available and they tend to have serious limitations due to high attrition rates and the tendency of participants to regain lost weight relatively quickly. Even for programs showing positive results, actual weight loss tends to be modest at best. A 2017 cover story in the New York Times Magazine, "Losing It," discussed research looking specifically at Weight Watchers which found that people rarely lost more than 5 percent of body weight over six months, and much of that weight was gained back within two years.
Even in studies looking at medically supervised very-low-calorie diets, patients who succeed in losing 15 to 25 percent of body weight tended to be the exception and, as with other commercial diet programs, many of them regained that weight fairly quickly.
Despite these failures, commercial weight-loss programs remain popular, largely due to aggressive advertising featuring success stories of people losing an astounding amount of weight (often with before and after pictures). That these success stories are outliers and that the vast majority of customers either lose little weight, drop out of the program after a few weeks, or regain the weight soon afterward, is typically glossed over.
Attrition remains a particular problem in weight loss programs as many people often drop out for various reasons, but since the dropouts are rarely counted in actual weight-loss claims, the numbers provided by these programs tend to be overinflated. More disturbing, studies looking at the health consequences of frequent dieting suggests that frequent weight loss and weight gain could potentially lead to long-term metabolic damage.
What is it that drives our perpetual obsession with becoming thinner? Esther D. Rothblum explores these questions in an intriguing new review article published in Archives of Scientific Psychology. A prominent feminist author and professor of women's studies at San Diego State University, Dr. Rothblum is an outspoken critic of the impact that the cultural obsession with thinness can have on health. She is also co-author of the Fat Studies Reader which focuses on the regular discrimination faced by people who are overweight. The multibillion-dollar diet industry is the chief beneficiary of this anti-fat obsession.
But she's hardly alone in condemning weight loss programs and the often disastrous effect they can have on health. In her article, Rothblum cites a number of recent critiques of dieting, including studies published by the American Psychological Association, the Centers for Disease Control and Prevention, and the National Institutes of Health, which suggest that being obsessed with losing weight is often counterproductive. And yet, despite ample evidence to the contrary, people continue to persist in the belief that they will be the exception.
In discussing the reasons why people choose to ignore the evidence that dieting doesn't work, Rothblum makes the following points:
- The idea of "calories in, calories out" sounds perfectly logical and, while this is certainly true, at least in theory, there are some important caveats. Our bodies have a way of adapting to changes in caloric intake in a very short time. After as little as two days, our metabolisms correct for a drop in the number of calories we take in. And this altered metabolism also helps ensure that we regain that lost weight relatively quickly, even after a year or more of dieting. For that matter, exercise is rarely that effective, since losing a single pound of fat means exercising enough to burn 3500 calories. This means that the standard formula of diet and exercise is never going to be enough to lose more than a minimal amount of weight.
- The claims made by commercial weight loss programs tend to be wildly exaggerated. Though we've all seen the ads featuring before and after pictures portraying once-obese customers having become thin and attractive, the suggestion that success is guaranteed usually places all the blame for failure on customers for lacking "willpower." What makes these claims so believable for many people is their own tendency to accept evidence that supports their beliefs while rejecting anything that contradicts them. For those desperate to lose weight, this often means setting aside their natural skepticism to accept often fantastic claims.
- Nonstop media images that represent thinness as being an essential part of attractiveness. For women, in particular, the typically underweight paragons of beauty shown in movies, television shows, and advertisements can make even average-sized women feel fat. And this message is increasingly accepted by men and children as well. That it often drives people to engage in unhealthy binge diets or even develop eating disorders is rarely addressed.
- Many health professionals, including physicians, psychologists, and dietary specialists, continue to lend their names to diets and weight loss programs that have little proven value. Though doctors often urge their patients to lose weight, the question of what constitutes a "healthy weight" is a loaded one. While it may be true that losing weight may provide health benefits, the risks associated with yo-yo dieting often exceed any possible gains this weight loss might produce.
- There is also the problem of how to define obesity in the first place. While the use of the body mass index (BMI) remains popular, largely because it is so easy to calculate, health and statistical experts have issued warnings about its limitations. Not only does BMI ignore the natural range in body size in the general population, but it also ignores the difference between muscle mass and fat mass. Studies suggest that most people labeled "obese" or "overweight" according to current definitions (such as having a BMI greater than 25) are in good health without any of the risks that have been associated with excessive weight.
- The diet industry encourages people to keep dieting no matter how ineffective it is. In the United States alone, more than $66 billion a year is spent on products and services associated with weight loss. This can include memberships in weight loss programs, weight-loss products (low-calorie foods, cookbooks, artificial sweeteners, and diet sodas), as well as expensive medical procedures such as liposuction and bariatric surgery. Although most of these products and services end up being useless, given that most people gain the weight back, customers continue to be drawn in by promises of quick weight loss and the belief that being thinner will make them attractive and more desirable. Perhaps more important, when a weight loss attempt fails, dieters typically blame themselves for lacking "willpower" rather than questioning the product or service.
So, is permanent weight loss possible? And why do so many health professionals ignore existing evidence that suggests otherwise? The diet industry is unlikely to go away anytime soon, but there are encouraging signs that sanity may eventually prevail. The Health at Every Size (HAES) movement has become more popular as a way of encouraging healthier alternatives for people of all body weights. Since its creation in the 1960s, HAES discards the "only thin is healthy" myth in favor of encouraging healthy eating and exercise for everyone. Not only does this put less pressure on obese and overweight people to try losing weight, but it also encourages them to develop a healthier lifestyle appropriate to their regular body weight.
The anti-fat stigma pushing people into unhealthy diets is pervasive in society, but groups like HAES promote a saner message that is beginning to be heard. Overcoming the anti-fat stigma and helping people accept themselves as they are represents a major challenge, but it is a challenge worth pursuing.
Rothblum, E. D. (2018). Slim chance for permanent weight loss. Archives of Scientific Psychology, 6(1), 63-69.