Appetite hormones spike when obese people diet, and stay high even a year after they have lost weight, researchers reported on Wednesday in a study that shows keeping weight off is more than a mere matter of willpower.
The Australian researchers said their report, published in Thursday’s issue of the New England Journal of Medicine, shows that dieters need some kind of help in controlling the compelling effects of these hormones if they are to keep the weight off.
“Furthermore, the activation of this coordinated response in people who remain obese after weight loss supports the view that there is an elevated body-weight set point in obese persons and that efforts to reduce weight below this point are vigorously resisted,” Priya Sumithran of the University of Melbourne and colleagues wrote.
In other words, the body rebels against eating less and tries hard to make the dieter eat, the researchers said.
“If this is the case, successful management of obesity will require the development of safe, effective, long-term treatments to counteract these compensatory mechanisms and reduce appetite.” They suggest that regulators should speed approval of any safe drugs that would do this.
The Australian team enrolled 50 overweight or obese patients without diabetes in a 10-week, very-low-calorie diet. They measured levels of various appetite-associated hormones including leptin, ghrelin, peptide YY and others as the patients dieted.
“One year after initial weight reduction, levels of the circulating mediators of appetite that encourage weight regain after diet-induced weight loss do not revert to the levels recorded before weight loss,” they wrote. “Long-term strategies to counteract this change may be needed to prevent obesity relapse.”
More than two-thirds of Americans are overweight or obese and their health care costs are among the factors keeping U.S. medical spending at the top of the chart globally. Obesity greatly raises rates of diabetes, heart disease, arthritis and some cancers.