The South Beach Diet continued...
However, many experts in diet and nutrition say the South Beach diet is more balanced and less risky than high-protein diets. The South Beach diet also distinguishes between beneficial carbs and those with little nutritional value. But the experts are more skeptical of this fad diet's emphasis on only eating foods that are low on the glycemic index. A food that has a low glycemic index by definition results in a slower and lower rise in blood sugar.
"My problem is that South Beach and some other diets teach people that bananas and carrots are bad because they have a high glycemic index," Geise tells WebMD. "But they're not bad because they're really high in good nutrients."
Again, the premise of the Zone rests on eating more protein and fewer carbohydrates than a traditional diet. So the same risks apply: a deficiency of vitamins, fiber, and other nutrients. But like the South Beach diet, the Zone is a little less severe in its attitude toward carbs than Atkins.
"In theory, the Zone is a more balanced diet, although I still don't think people on it are getting enough carbohydrates," says Zied.
The Zone may pose a different sort of nutritional risk. "The Zone relies so much on the numbers that it's hard to follow," Geise says. "People just throw up their hands because they don't know how to get into the Zone." That kind of confusion can make it easy for people to lose track of their nutritional needs.