It's particularly important, nutritionists point out, for adolescents, the elderly, the poor, pregnant women, and those with psychiatric or chronic medical illness to be cautious. These folks are most at risk for inadequate nutrition. Still, the Academy of Nutrition and Dietetics says that a well-planned vegan diet is appropriate even for babies.
Diehard meat- and fish-lovers who aren't trying to clean out their arteries can aim instead for what David Katz, a clinical instructor of medicine at Yale University and founding director of the Yale-Griffin Prevention Research Center, calls "an optimal omnivorous diet." An eating plan on the Ornish spectrum is one good option. Another is the Mediterranean diet.
There actually isn't a single Mediterranean diet; the term describes a style of eating that emphasizes fruits, veggies, whole grains, beans, nuts, legumes, olive oil, and herbs and spices. Followers eat fish and seafood at least a couple of times a week; enjoy poultry, eggs, cheese, and yogurt in moderation; and save sweets and red meat for rare occasions. Healthier mono- and polyunsaturated fats are subbed—in moderation—for saturated fats, and meals are often topped off with a splash of red wine. The diet has been linked with a decreased risk for heart disease, and it's also been shown to reduce blood pressure and LDL cholesterol. "You can get similar benefits out of a Mediterranean-style diet as you can a vegan diet," says Lawrence Cheskin, director of the Johns Hopkins Weight Management Center in Baltimore. And while head-to-head studies are lacking, the Mediterranean approach removes concerns about getting sufficient omega-3 and omega-6 fatty acids, vitamin B12, and calcium.
The bottom line? Healthful diets fall on a continuum, and most nutritionists would agree that veganism is far superior to the typical American regimen. But the healthful choices that work best for you are the ones that actually work for you.
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Angela Haupt is a health reporter for U.S. News & World Report. You can follow her on Twitter or reach her at email@example.com.