Atkins works only by cutting needed carbs, expert says

By Karen Haram, San Antonio Express-News

November 17, 2003

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If you are not on the Atkins diet, you probably know someone who is.

Depending on whom you talk to, you will hear claims of fantastic success, predictions of dire problems - and everything in between.

What is the truth?

For answers, I turned to nutrition expert Ed Blonz, a food and health expert with a doctorate in nutrition. Formerly on the faculty at the University of Minnesota, Blonz is a Fellow of the American College of Nutrition in Clearwater, Fla., has written seven books on food, health and nutrition and was a featured speaker at the Association of Food Journalists' conference in Boston in October.

Following are Blonz's answers to questions about the safety and efficacy of Atkins and similar weight-loss plans.

Q - In simple terms, why do you lose weight on low-carbohydrate diets?

A - Low-carbohydrate weight-loss diets can appear to be very attractive because they can deliver a significant loss of weight in a relatively short period of time. There's a catch, however, in that aside from being restrictive, quickly lost weight tends to be rapidly regained when you go off the diet. For this reason these diets are of questionable merit for most individuals.

Here's how these diets work. When you eat only protein and fat you have effectively eliminated your body's intake of carbohydrates. This threatens the body's access to glucose. Although the fat stored in the body is our major energy reserve, the body needs small amounts of glucose to help it burn the fat correctly.

Without carbohydrates (glucose), the fats are incompletely burned. The remnants of this incomplete combustion, called ketone bodies, begin to appear. As ketones can be toxic if allowed to accumulate, the body starts to eliminate them through the kidneys via the urine.

The resulting condition is called ketosis, and it also occurs in uncontrolled diabetes when there's insufficient insulin to let glucose into the energy-producing (fat-burning) cells of the body. In either case, uncontrolled ketosis can upset the body's chemical balance and give rise to a dangerous condition called acidosis.

Not having enough glucose, though, means more than producing ketones. The red blood cells have an absolute requirement for glucose, and the brain requires small amounts as well. So when the diet doesn't supply any carbohydrate, the body begins to scavenge around for potential sources of glucose among its own tissues.

Body protein can be used because some of the amino acids in protein can be turned into glucose. The muscles represent the body's largest reserve of protein, and like all protein tissues they are about 80 percent water by weight. When the body begins to take apart its proteins to make glucose, all this water weight gets released and eliminated, and like magic your weight begins to drop.

The shortage of glucose has another side effect in that you won't be bursting with get-up-and-go energy. Sure, you'll be losing some weight, but it's important to realize that a large percentage of the lost weight will be body water (a byproduct of the ketosis).

This weight is quickly regained once one reintroduces carbohydrates. The bottom line is that a low/no carbohydrate diet is a questionable way to lose weight. And besides, who wants to live their life without carbohydrates?

Q - Is it safe to stay on low-carbohydrate diets for a lifetime?

A - Theoretically I would say yes, but it would only be for a "low" carb diet and not a "no" carb diet. If consuming a small amount of carbohydrates, there would need to be a special emphasis on sourcing your available carbs from wholesome, nutrient-rich vegetables and fruits.