Health risks of high protein diets.
Your high-protein diet may help you lose weight, but it could also increase your risk of osteoporosis. Recent research in the
Journal of Gerontology found that overweight postmenopausal women on a weight-loss diet who ate meaty, protein-rich
diets lost bone density faster than those who consumed moderate-protein vegetarian diets.
In the study, one group of women ate a meat-free diet made up of 18 percent protein; another group followed a diet of 30
percent protein (from pork, dairy, egg and vegetarian sources). Both groups lost an average of 19 pounds over 12 weeks, but
the meat-eaters lost bone density too. (The researchers examined the effects of protein from chicken and beef and found
“Meat contains high levels of sulfur-containing amino acids that promote acid production, and that acid load may promote bone
breakdown,” says Wayne W. Campbell, Ph.D., professor of foods and nutrition at Purdue. Postmenopausal women’s bone health is
already compromised by a natural decrease in bone-protecting estrogen.
Campbell recommends that, for bone health, postmenopausal women get adequate, not excessive, protein—between 16 and 18
percent of calories (that’s 50 to 56 grams in a 1,250-calorie diet, which is about what the women in the studies ate), with
an emphasis on plant-based sources. Top sources of plant-based proteins include beans, lentils, whole grains and nuts.