Hollywood star Gwyneth Paltrow revealed this week that she has osteopenia at the age of 37. The revelation by the actress has many experts wondering whether her much-publicized macrobiotic and largely vegan diet may be to blame. Paltrow's diet was essentially devoid of dairy products, healthy fats, and protein, and the actress was told by her doctors that she had the lowest vitamin D level they'd seen. Osteoporosis experts say that excessive dieting and over-exercising are well-known risk...