What's Your Diet Deficit?

Last Editorial Review: 1/31/2005

Many fad diets leave out more than the carbs, fat, or extra calories

By R. Morgan Griffin
WebMD Weight Loss Clinic - Feature

Reviewed By Brunilda Nazario

Anyone who's on a fad diet is painfully aware of some things now missing from the dinner plate. Oh, how you yearn for the simple things you took for granted -- the burger with the bun, the fast food bagel that didn't require your scraping three-quarters of the cream cheese off with a napkin, the simplicity of pouring a container of half-and-half into your coffee instead of letting the mug grow cold while you wait for the waitress to bring the pitcher of skim milk.

But not everything that your diet plan prohibits leaves such an obvious hole in your life. That may not be a good thing. Without your noticing it, your fad diet may be cutting out foods that give you important vitamins and nutrients you really need.

While losing weight is obviously great for your health, it isn't the only thing you need to worry about. But that's all any fad diet is designed to do. Good nutrition is often beside the point.

"I think people lose sight of nutrition when they're dieting," says Elisa Zied, RD, a spokeswoman for the American Dietetic Association. "But if you're not getting good nutrition, you're not going to feel well."

So besides those much-missed French fries and ice cream, what might you be leaving out of your diet? WebMD talked to some experts to find out what's missing from fad diet plans. In some cases, it may be quite a lot.

Do I Really Need to Worry About Nutrition?

Obviously, we don't mean to overstate the problem. You won't drop dead from a nutritional deficiency after a few months of following a fad diet plan. Our nation's emergency rooms aren't flooded with fad dieters laid low by scurvy and rickets.

But it's easy to underestimate the problem, too. Chronic nutritional deficiencies can make you feel rundown and unwell.

"I definitely see people who have nutritional problems from dieting," Zied tells WebMD. "You need to get laboratory tests to make sure. But sometimes it's obvious. Their skin is sallow, their lips are cracking, or they have bad breath."

Nutritional deficiencies can lead to more serious problems too, especially for people who already have other medical conditions. Many vitamins and nutrients have been shown to help prevent serious diseases, like cancer and heart disease. Sticking to an imbalanced diet for a long time may lead to serious consequences.

High-Protein Diets

High-protein/low-carb fad diets have come under some heavy criticism from the experts.

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 problems.
  • 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 dangerous.

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.

"Consider that any fad diet that requires you to take supplements might not be healthy in the long run."

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."

The Zone


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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.

Vegetarianism and Veganism

When it's done sensibly, the experts say that vegetarianism can be a healthy diet. One of the most obvious problems with cutting out meat is that you may not get enough protein.

"The problem for some people on vegetarian and vegan diets is that they cut out the meat but don't replace it," says Geise. "You can't just sustain yourself on vegetables and grains."

However, if you still eat milk and eggs, you should be OK. Vegans, who don't eat animal products of any kind, are in a trickier position, but they can get protein from foods like beans, legumes, nuts, and seeds, Zied says.

Protein isn't the only issue. "If you're a strict vegan, you are risking some nutritional deficiencies," says Zied. "Zinc, iron, and B-12 are only in foods that come from animals."

The only way to get these vitamins and minerals is through artificial means. You can either buy foods that are fortified -- such as some brands of soy milk or veggie burgers -- or take supplements.

Other Diets

There are simply too many fad diets to go through all of them in any detail -- a walk down the diet aisle at a local bookstore will tell you that. Since new ones are coming out all the time, you need to exercise some common sense when evaluating them.

The experts say any diet that hinges on cutting out or sharply reducing one type of food puts you at risk of nutritional problems. Any of these fad diets may help you lose weight in the short term. Whether you cut out high-fat foods, carbohydrates, or food with a high glycemic index, or if you subsist only on grapefruits and bowls of cabbage soup, you'll probably lose weight. But you'd probably lose weight if you decided to forgo all red and yellow foods, or foods beginning with vowels. That doesn't mean it's a sensible nutritional approach. "You have to eat from a wide variety of foods," Geise tells WebMD.

But a lack of variety is not the only risk: Any diet that keeps you at a very low number of calories can be a problem, even if you're eating healthy food.

Rapid weight loss on any fad diet can also cause problems, such as gallstones.

Aside from the nutritional problems, the experts say that very strict diets have other drawbacks. For one, they're hard to stick to. It's easier to stay on a meal plan that's a little more forgiving.

Are Supplements the Answer?

Still, you might wonder if any of this worrying about nutrition still matters in the age of that scientific wonder, the nutritional supplement. But can you really atone for your nutritional sins at the end of the day with a handful of pills?

"A lot of my patients see supplements as a quick fix," says Geise, "But a pill is just not the same thing as getting these nutrients in your food."

The fact is that the science isn't good enough yet. We just haven't been able to discover, isolate, and manufacture all of the nutritious things that occur naturally in foods.

"A supplement will never give you all the phytochemicals that you can get from fruits and vegetables," says Zied. "Supplements aren't a panacea for the problems of an imbalanced diet."

Besides, you should consider that any fad diet that requires you to take supplements might not be healthy in the long run.

"If your diet pushes supplements, that's a red flag," says Zied. "And if it's pushing its own line of supplements, you really have to be suspicious."

Modifying Your Diet

So what if your fad diet plan isn't giving you all of the nutrition you need? Do you have to scrap it and start over?

Not at all, say the experts. Instead, if you like the diet you're on, you can just make some changes to make it healthier. The key is to hang on to the beneficial aspects of these fad diets while filling some of the nutritional holes.

For instance, Geise tells patients, "If you don't ever want to eat white bread or white rice for the rest of your life, that's fine. But you need to get some more healthy carbohydrates in your diet." That way, she says, "patients feel like they're still sticking to the diet, but making it a little healthier. It's just modified a little." You may want the help of your doctor or a nutritionist in figuring out how to make these changes.

In the end, you need not only a diet, but also a sensible meal plan that you can stick to for life, says Magee. While you may not want to hear it, you need to get regular exercise, too. Using common sense and moderation may not be a quick fix, but it will help.

"I know it sounds so boring," says Zied. "But the data shows that a sensible diet and exercise are the only things that work in the long run."

Published Sept. 27, 2004.

SOURCES: Tara Geise, RD, MS, spokeswoman, American Dietetic Association. Elaine Magee, MPH, RD, WebMD Weight Loss Clinic "Recipe Doctor"; author, Fry Light, Fry Right. Elisa Zied, RD, spokeswoman, American Dietetic Association. Bratman, S. and Knight, D. Health Food Junkies, New York: Broadway Books, 2000. The American Dietetic Association.

©1996-2005 WebMD Inc. All rights reserved.


According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

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