Exercise reduces hunger in lean women but not obese women

June 17, 2008

Exercise does not suppress appetite in obese women, as it does in lean women, according to a new study. The results were presented Tuesday, June 17, at The Endocrine Society's 90th Annual Meeting in San Francisco.

"This [lack of appetite suppression] may promote greater food intake after exercise in obese women," said Katarina Borer, PhD, a University of Michigan researcher and lead author of the study. "This information will help therapists and physicians understand the limitations of exercise in appetite control for weight loss in obese people."

Borer and her co-workers sought to better understand how changes in body fat level influence appetite and a hormone called leptin, which in animals curbs appetite when body fat increases. When leptin levels rise, it supposedly shuts off appetite and motivates physical activity to burn calories. However, as obese people become fatter, their leptin levels rise, but they become resistant to the actions of this hormone.

"The hormone doesn't do the job it's supposed to do in lean people," Borer said.

In research funded by the National Institutes of Health, Borer's group studied 20 postmenopausal women: 10 lean and 10 obese women. The women ate three weight-maintenance meals a day while participating in three experiments on three separate days. During one experiment they did not exercise.

In the other two experiments the women exercised on a treadmill in the morning and the afternoon. They burned 500 calories each time, for a total of 1,000 calories a day. These two experiments differed by exercise intensity. One involved walking at high intensity, or 80 percent of maximal effort, for 7.5 minutes, with 10-minute rest periods between 10 walking sessions. The other experiment was half as intense (40 percent of peak effort) and involved walking for 15 minutes and resting for 5 minutes.

Every hour and before each meal, subjects recorded their appetite level on a 10-point scale ranging from not at all hungry to extremely hungry. Blood samples were collected every 15 to 60 minutes for hormone measurements.

Obese women claimed they were less hungry than lean women before meals and reported no appetite suppression during exercise, Borer said.

As expected, obese women had much higher leptin levels than in lean women, study data showed. But during intense exercise, obese women did not have reduced production of leptin, as lean women did. Only moderate-intensity exercise lowered leptin in obese women.

"Obesity interferes with leptin's detection of exercise energy expenditure and with appetite suppression," Borer said. "Obese women perhaps need to consciously watch their calories because some of the hormonal satiety [fullness] signals don't seem to work as well."

Source: The Endocrine Society

Explore further: Research highlights 7 essential ingredients for healthy adolescents

Related Stories

Is 'when we eat' as important as 'what we eat'?

June 21, 2016

In a review of research on the effect of meal patterns on health, the few studies available suggest that eating irregularly is linked to a higher risk of metabolic syndrome (high blood pressure, type 2 diabetes and obesity). ...

Early and late menopause can increase risk of type 2 diabetes

July 27, 2016

Women who begin menopause before age 45 or after 55 have an increased risk of developing type 2 diabetes, according to a study of more than 124,000 women enrolled in the Women's Health Initiative, a large national trial aimed ...

Study compares effectiveness of weight-loss drugs

June 14, 2016

In an analysis that included nearly 30,000 overweight or obese adults, compared with placebo, orlistat, lorcaserin, naltrexone-bupropion, phentermine-topiramate, and liraglutide were each associated with achieving at least ...

Brain stimulation to reduce food cravings? The data so far...

July 19, 2016

Available research suggests that noninvasive stimulation of a specific brain area can reduce food cravings—particularly for high-calorie, "appetitive" foods, according to a review in the Psychosomatic Medicine: Journal ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Cow embryos reveal new type of chromosome chimera

May 27, 2016

I've often wondered what happens between the time an egg is fertilized and the time the ball of cells that it becomes nestles into the uterine lining. It's a period that we know very little about, a black box of developmental ...

Shaving time to test antidotes for nerve agents

February 29, 2016

Imagine you wanted to know how much energy it took to bike up a mountain, but couldn't finish the ride to the peak yourself. So, to get the total energy required, you and a team of friends strap energy meters to your bikes ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.