Not your fault! Hormones linked to weight regain

By MALCOLM RITTER , AP Science Writer

Any dieter knows that it's hard to keep off weight you've lost. Now a study finds that even a year after dieters shed a good chunk of weight quickly, their hormones were still insisting, "Eat! Eat! Eat!"

The findings suggest that dieters who have regained weight are not just slipping back into old habits, but are struggling against a persistent biological urge.

"People who regain weight should not be harsh on themselves, as eating is our most basic instinct," Joseph Proietto of the University of Melbourne in Australia, an author of the study, said in an email. The research appears in Thursday's issue of the .

Weight regain is a common problem for dieters. To study what drives it, Proietto and his colleagues enrolled 50 or in a 10-week diet program in Australia. They wanted to see what would happen in people who lost at least 10 percent of their body weight. Ultimately, only 34 people lost that much and stuck with the study long enough for analysis.

The program was intense. On average, the participants lost almost 30 pounds during the 10 weeks, faster than the standard advice of losing 1 or 2 pounds a week. They took in 500 to 550 calories a day, using a meal replacement called Optifast plus vegetables for eight weeks. Then for two weeks they were gradually reintroduced to ordinary foods.

Despite counseling and written advice about how to maintain their new weights, they gained an average of 12 pounds back over the next year. So they were still at lower weights than when they started.

The scientists checked the of nine hormones that influence appetite. The key finding came from comparing the from before the weight-loss program to one year after it was over. Six hormones were still out of whack in a direction that would boost hunger.

The also rated themselves as feeling hungrier after meals at the one-year mark, compared to what they reported before the diet program began.

Experts not connected to the study said the persistent effect on levels was not surprising, and that it probably had nothing to do with the speed of the weight loss.

People who lose less than 10 percent of body weight would probably show the same thing, though to a lesser degree, said Dr. George Bray of the Pennington Biomedical Research Center in Baton Rouge, La.

A key message of the study is that "it's better not to gain weight than to try to lose it," Bray said.

Why would a dieter's body rebel against weight loss? It's an evolutionary holdover from earlier times, when weight loss could threaten survival and reproduction, says Dr. Rudolph Leibel, an obesity expert at Columbia University in New York. So "it's not surprising at all" that our bodies would fight back for at least a year, he said. "This is probably a more or less permanent response."

People who lose significant weight not only gain bigger appetite but also burn fewer calories than normal, creating "a perfect storm for weight regain," Leibel said.

He said avoiding appears to be a fundamentally different problem from losing weight in the first place, and that researchers should pay more attention to it.

The study was supported by the Australian government, medical professional groups and a private foundation. Proietto served on a medical advisory board of Nestle, maker of Optifast, until last year.

More information: New England Journal of Medicine: http://www.nejm.org

5 /5 (2 votes)
add to favorites email to friend print save as pdf

Related Stories

Appetite hormones may predict weight regain after dieting

Sep 09, 2010

Many people have experienced the frustration that comes with regaining weight that was lost from dieting. According to a new study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Me ...

Study shows why weight gain is inevitable

May 09, 2006

Denmark's National Exercise and Nutrition Council says it has found people cannot lose more than 5 percent to 10 percent of their weight through dieting.

Lose weight fast for lasting results, suggests new study

May 06, 2010

If you thought the best way to lose and maintain weight was the slow and steady approach, think again. A new study by Lisa Nackers and colleagues, from the University of Florida in the US, suggests that the key to long-term ...

'Yo-yo' effect of slimming diets explained

Jan 12, 2011

If you want to lose the kilos you've put on over Christmas, you may be interested in knowing that the hormones related to appetite play an important role in your likelihood of regaining weight after dieting. ...

Recommended for you

Study recommends inmate immunity test

11 hours ago

(AP)—Federal experts are recommending that California test inmates for immunity to a sometimes fatal soil-borne fungus before incarcerating them at two Central Valley state prisons where the disease has killed nearly three ...

Down syndrome teens need support, health assessed

18 hours ago

Young adults with Down syndrome experience a range of physical and mental health conditions over and above those commonly reported in children with the condition—and these health problems may significantly ...

Time out for exercise

18 hours ago

University of Queensland researcher has found that restructuring our daily routine to include exercise can have unexpected effects on health.

User comments