Weight Loss Can Mean Bone Loss
Dieters Who Don't Exercise at Risk for Weaker Bones
Dec. 11, 2006 -- Overweight dieters who cut calories but don't exercise lose
more than weight -- they lose bone mass.
That finding comes from a study by Dennis T. Villareal, MD, and colleagues
at Washington University in St. Louis.
The researchers studied 46 men and women with an average age of 57. All were
overweight; none got regular exercise.
In other words, they were typical Americans.
For the study, 36 of the participants agreed to lose weight. Half of them
ate less -- about 20% fewer calories. The other half worked out more -- burning
off about 20% more calories.
For comparison, 10 more participants got advice on healthy lifestyles but
didn't diet or exercise.
What happened? Compared with the 10 who only got advice, the dieters and the
exercisers both lost weight.
But, unlike the exercisers, the dieters lost more than weight. They lost
And they lost it in the areas where elderly people are most likely to suffer
fractures: their spines, their hips, and their upper legs.
"Calorie restriction is beneficial, but if you don't combine it with
exercise you lose bone," Villareal tells WebMD. "You don't have to do
it the way these people did, with exercise only.
"If you change your diet and exercise at the same time, it is a win/win
situation," Villareal says.
Leslie Bonci, MPH, RD, director of sports nutrition at the University of
Pittsburgh, notes that exercise stimulates bone growth.
If you just cut calories -- and don't exercise -- you harm your bones two
ways. You may cut nutrients needed to maintain strong bones, and you don't
stimulate bone growth.
"Moving is such a critical component of dieting," Bonci tells
"You might get lighter without exercise -- but that's because you have
less skeleton than you did before. That is a really big concern for people as
they age," she says.
The Villareal study suggests exercise can counteract the bone-loss effect of
dieting, says Edward Puzas, PhD, professor of orthopaedics at the University of
Rochester in New York.
"If you are trying to lose weight and protect your skeleton, especially
if you are an older adult, mixing diet with exercise would be best for
protecting your bones," Puzas tells WebMD.
The Villareal study appears in the Dec. 11/25 issue of Archives of