The reason so many people find it harder to keep weight off than it is to lose it is hormonal, researchers in Denmark found in a recent study, as hormones need time to rebalance to exist at the lower weight. Photo by Roman Globa/Shutterstock

COPENHAGEN, Denmark, April 14 (UPI) -- Many people lose weight through diet and exercise, only to find it as difficult, or harder, to keep the weight off than it was to lose it.

Researchers in Denmark found obese people who lose weight can avoid this if they maintain their initial weight loss for at least a year, retraining the way their bodies process food.


The study showed it takes about that long for two hormones regulating appetite to adjust to a lower "set point" for body weight after weight loss. Before these hormones adjust to the new normal, the body fights the lower weight, making it more challenging to maintain weight loss, similar to the difficulty associated with attempting to change the eating and exercise habits that led to obesity.

"The interesting and uplifting news in this study is that if you are able to maintain your weight loss for a longer period of time, it seems as if you have 'passed the critical point,' and after this point, it will actually become easier for you to maintain your weight loss than is was immediately after the initial weight loss," Signe Sørensen Torekov, an associate professor at the University of Denmark, said in a press release. "Thus, the body is no longer fighting against you, but actually with you, which is good news for anyone trying to lose weight."

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For the study, published in the European Journal of Endocrinology, researchers recruited 20 obese but healthy people, who lost 13 percent of their weight during an 8-week low-calorie diet. The participants were then entered into a maintenance program for 52 weeks, with researchers monitoring plasma levels of glucagon-like peptide 1, peptide YY, ghrelin, glucose-dependent insulinotropic polypeptide and glucagon each week.

Over the course of the year, the researchers found the levels of GLP-1 and PYY, which inhibit appetite, increased while ghrelin, a hunger-related hormone, increased immediately after weight loss but returned to normal levels.

The increase in ghrelin was directly related to the body thinking it required more food to maintain it's previous weight, researchers said, but the other two hormones increased over time as the body accepted the participants new base weight.

"This study shows that if an overweight person is able to maintain an initial weight loss -- in this case for a year -- the body will eventually 'accept' this new weight and thus not fight against it, as is otherwise normally the case when you are in a calorie-deficit state," Torekov said.