Drugs Physical Activity Surgery and Other Treatment for Overweight and Obesity - Might Weight Loss Be Harmful?

Successful weight-loss treatments generally result in reduced blood pressure, reduced triglycerides, increased HDL cholesterol, and reduced total cholesterol and LDL cholesterol. Weight loss of as little as 5% to 10% of initial weight produces measurable health benefits and may prevent illnesses among people at risk. These findings suggest that treatment should not exclusively focus on the medical consequences of obesity, but obesity itself should be treated. The NIH recommends weight loss for people with BMI greater than 30 and for those with BMI greater than 25 with two or more obesity-related risk factors. The NIH guidelines recommend that for people with BMI between 25 and 30 without other risk factors, the focus should be prevention of further weight gain, rather than weight loss.

In "Obesity: What Mental Health Professionals Need to Know," Devlin reported that critics cite the health and psychological risks of "weight cycling"—continuously pursuing weight loss in the diet-weight loss/weight regain cycle known as "yo-yo dieting" as even greater than the risks associated with obesity. They assert that multiple unsuccessful efforts to lose weight demoralize people, make future weight loss even more challenging, and that dietary treatment of obesity may trigger or worsen binge eating among people who are obese. They also offer several studies that have found an association between weight cycling and increased morbidity and mortality as evidence of the dangers of dieting.

In "Screening and Interventions for Obesity in Adults: Summary of the Evidence for the U.S. Preventive Services Task Force" (Annals of Internal Medicine, vol. 139, no. 11, December 2, 2003), Kathleen McTigue and her colleagues also reviewed the studies that revealed a link between weight cycling and mortality. The investigators found that some studies failed to distinguish between intentional and unintentional weight loss. In the research considering the relationship between weight cycling with intentional weight loss, some studies have found unfavorable effects on coronary heart disease and its risk factors and others have not. They also found data suggesting that weight-cycling risk increases inversely with BMI—the higher the BMI, the lower the risk of weight cycling. If these findings are correct, then people suffering from obesity as opposed to overweight are at less risk of morbidity and mortality attributable to weight cycling.

Is It Better to Be Overweight?

Two studies published in the April 2004 issue of the Journal of the American Medical Association found less risk associated with overweight than previously thought. One study, conducted by investigators from the National Cancer Institute and the Centers for Disease Control and Prevention found that increased risk of death from obesity was mostly among the extremely obese, a group constituting of just 8% of Americans. The researchers also found that extreme thinness carried a slight increase in the risk of death. The study did not explain how or why being slightly overweight afforded protection but researchers speculate that it is because most people die when they are over 70. Being mildly overweight in old age may be protective, because it gives rise to more muscle and more bone.

The other study examined forty-year trends in cardiovascular disease (CVD) risk factors by BMI groups among adults aged twenty to seventy-four years found that except for diabetes, CVD risk factors have declined considerably over the past forty years in all BMI groups. Although obese people still have higher risk-factor levels than lean people, the levels of these risk factors are much lower than in previous decades. The investigators observed that obese people today have better CVD risk factor profiles than their leaner counterparts did twenty to thirty years ago; however, they suggested that other factors, such as effective treatment to reduce cholesterol and blood pressure as well as the decreased prevalence of smoking, might explain the improved profiles of obese people (Edward W. Gregg et al., "Secular Trends in Cardiovascular Disease Risk Factors According to Body Mass Index in U.S. Adults" Journal of the American Medical Association, vol. 293, no.15, April 20, 2005).

While the government continued to warn that excess weight is a major threat to the 65% of adult Americans who are either overweight or obese, that is not the message that many people heard in the report from the CDC researchers. The media claimed that the public interpreted these data as an endorsement of overweight and a reason to abandon, or at least relax, their efforts to diet and lose weight. Interviewed for an article in the New York Times in May 2005, Dan Mindus, a senior analyst for the Center for Consumer Freedom, a lobbying group underwritten by the food industry, asserted, "The federal government had told us that your love handles were going to kill you. Now people understand that being overweight is probably a little healthier than being thin" (Timothy Egan, "With Potbellies Back In, Buffet Pots Are Humming," New York Times, May 3, 2005).