What's Your Diet Deficit?
Many fad diets leave out more than the carbs, fat, or extra calories.
High-protein/low-carb fad diets have come under some heavy criticism from
Zied speaks specifically about the Atkins diet, although many high-protein
diets are what she calls "imbalanced diets." "By cutting out
carbohydrates, it eliminates the food that is supposed to be the main source of
fuel for your body," says Zied.
Many of the high-protein diets ignore the nutritional differences between
different kinds of carbohydrates, experts say. But there's a world of
difference -- nutritionally speaking -- between carbohydrates like refined
sugar and a kiwi, says Elaine Magee, MPH, RD, the "Recipe Doctor" for
WebMD's Weight Loss Clinic and the author of Fry Light, Fry Right.
So what specifically might someone on a high-protein diet be missing?
Fiber, which is in many of the carbohydrates that are
eliminated in high-protein diets, helps with digestion. It may also help
prevent some serious diseases, such as heart disease.
Water. "Carbohydrates have a lot of water in
them," says Zied. "So when you cut them out, it's easy to get
dehydrated without realizing it."
Vitamins, such as A, B, C, and E, are
plentiful in many high-carb vegetables, fruits, and grains.
Folic acid is in dark leafy greens and fruits and
vegetables. It's also in many fortified foods, like cereals, that Atkins
prohibits. Folic acid may reduce the risk of cancers, heart disease, and other
Phytochemicals and antioxidants are in whole grains,
fruits, and vegetables. "We know that these things can help prevent a lot
of different diseases, including heart disease and cancer," says Tara
Geise, RD, a spokeswoman for the American Dietetic Association.
Many experts also believe that high-protein diets allow far too much fat.
And even protein can be a problem in large amounts. "Overloading on protein
can harm your kidneys and affect your fluid balance," says Zied. For some
people, especially people who already have kidney problems, these diets may be
The South Beach Diet
The South Beach diet emphasizes an initial phase of low carbs but later
changes to add more "good carbs." With this diet, you may be in danger
of not getting enough fiber, vitamins A, B, C, and E, and important
phytochemicals and antioxidants from carbohydrates.