Osteoporosis and Diets
Does Weight Loss Put You at Risk?
The Impact of Crash Dieting on Bone Health
Even if you’re not “small-boned” or particularly thin, long-term “crash” dieting can have an impact on your bone health, Cosman says.
“If you go for six months or so eating 800 or 900 calories a day, that’s likely to be bad for your bones. I would say that a threshold of at least 1,200 calories per day is about what’s needed to maintain your bones and tissues. If your caloric intake is significantly below that for an extended period of time, you’re probably doing damage.”
“I don’t think adults should be under 1,200 calories a day,” agrees Beatrice Edwards, MD, MPH, associate professor of medicine and director of the Bone Health and Osteoporosis Center at Northwestern University’s Feinberg School of Medicine. “Below that, you’re putting yourself at risk.”
Even if you don’t have an eating disorder, you could be damaging your bones with “disordered eating,” Edwards says.
“I know a lot of women like this. They have very hectic lifestyles -- maybe they’re on the phone with Japan trading stocks and they have a power bar for breakfast, a cup of coffee for lunch, and a Lean Cuisine for dinner,” she says. “It’s not a ‘syndrome,’ but it’s happening, and people who do that are losing not only bone but muscle structure.”
How Can You Lose Weight and Preserve Bone Health at the Same Time?
Try the old-fashioned way, Edwards says. “No grapefruit diets!” She recommends balanced meal plans like those of Weight Watchers and Jenny Craig. “I particularly like Weight Watchers, because they say that after 50, women need three dairy servings a day and calcium supplements.”
If you’re restricting calories over a longer period of time (more than a few weeks), it’s particularly important to pay careful attention to the nutrients you’re getting, Kitchin says. “If you’re cutting out calcium with the calories you cut, that could definitely be an independent risk factor for osteoporosis.”
Whatever your diet, you should be getting 1,000 mg of calcium and 400-800 IU of vitamin D daily if you’re under 50. If you’re over 50, you need 1,200 mg of calcium and 800-1,000 IU of vitamin D daily.