Calorie restriction does not appear to induce bone loss in overweight adults

Sep 22, 2008

Young adults who follow a diet that is low in calories but nutritionally sound for six months appear to lose weight and fat without significant bone loss, according to a report in the September 22 issue of Archives of Internal Medicine.

Calorie restriction is the only intervention known to decrease the rate of biological aging and increase longevity, according to background information in the article. However, it is well known that chronic energy deficiency impairs bone mineral uptake and that weight loss is associated with bone loss in obese individuals. Calorie restriction, therefore, could also lead to bone loss and fracture.

Leanne M. Redman, Ph.D., and colleagues at Pennington Biomedical Research Center, Baton Rouge, La., studied 46 healthy, overweight men and women (average age 37) who were randomly assigned to one of four groups for six months. Eleven formed the control group, assigned to eat a healthy diet; 12 were assigned to consume 25 percent fewer calories than they expended per day; 12 were assigned to create a 25 percent energy deficit through eating fewer calories and exercising five days per week; and 11 ate a low-calorie diet (890 calories per day) until they achieved 15 percent weight loss, at which time they switched to a weight maintenance plan. All diets included recommended levels of vitamins and minerals, including calcium, and contained 30 percent fat, 15 percent protein and 55 percent carbohydrates, based on American Heart Association guidelines.

After six months, average body weight was reduced by 1 percent in the control group, 10.4 percent in the calorie restriction group, 10 percent in the calorie restriction plus exercise group and 13.9 percent in the low-calorie diet group.

Bone mineral density and blood markers of bone resorption and formation (processes by which bone is broken down and regenerated on a regular basis) were measured at the beginning of the study and again after six months. "Compared with the control group, none of the groups showed any change in bone mineral density for total body or hip," the authors write. Markers of bone resorption were increased in all three intervention groups, while markers of bone formation were decreased in the calorie restriction group but were unchanged in the low-calorie diet or calorie restriction plus exercise group.

"Our data do not support the notion that extreme weight loss (more than 10 percent) over short periods (three months) has a worse prognosis on bone health than gradual weight loss achieved over six months by moderate calorie restriction with or without aerobic exercise," the authors write. "We speculate that in young individuals undergoing calorie restriction, minor adjustments in bone occur as a normal physiological adaptation to the reduced body mass. Further studies of longer duration are warranted and should include an assessment of bone architecture to ensure that bone quality is preserved with weight loss."

Source: JAMA and Archives Journals

Explore further: AMA examines economic impact of physicians

add to favorites email to friend print save as pdf

Related Stories

DARPA wants your ideas for a 100-year starship

May 23, 2011

The idea for a 100-year starship has been tossed around recently, and now DARPA the Defense Advanced Research Projects Agency, has put out a Request for Information (RFI) looking for ideas about how a long-term ...

Recommended for you

AMA examines economic impact of physicians

13 hours ago

(HealthDay)—Physicians who mainly engage in patient care contribute a total of $1.6 trillion in economic output, according to the American Medical Association (AMA)'s Economic Impact Study.

Less-schooled whites lose longevity, study finds

13 hours ago

Barbara Gentry slowly shifts her heavy frame out of a chair and uses a walker to move the dozen feet to a chair not far from the pool table at the Buford Senior Center. Her hair is white and a cough sometimes interrupts her ...

How to keep your fitness goals on track

14 hours ago

(HealthDay)—The New Year's resolutions many made to get fit have stalled by now. And one expert thinks that's because many people set their goals too high.

Suddenly health insurance is not for sale

Apr 18, 2014

(HealthDay)— Darlene Tucker, an independent insurance broker in Scotts Hill, Tenn., says health insurers in her area aren't selling policies year-round anymore.

User comments : 0

More news stories

Cancer stem cells linked to drug resistance

Most drugs used to treat lung, breast and pancreatic cancers also promote drug-resistance and ultimately spur tumor growth. Researchers at the University of California, San Diego School of Medicine have discovered ...

Finnish inventor rethinks design of the axe

(Phys.org) —Finnish inventor Heikki Kärnä is the man behind the Vipukirves Leveraxe, which is a precision tool for splitting firewood. He designed the tool to make the job easier and more efficient, with ...

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.