Fasting

Ads for popular juice fasts like The Original Celebrity Juice Diet or The Master Cleanser may claim you'll lose pounds in just days, but experts agree that these programs do more to your body than take off some temporary weight. Keep reading to find out what effect fasting really has on your body and the bottom line from experts.

What Fasts Do to the Body
When subjected to a fast, the body burns up stored carbohydrates within 24 hours and then switches to using fat as its energy source. This may sound like a dream to a dieter, but in reality it's not good for the body. Why? Because red blood cells as well as the cells of the brain and central nervous system need carbohydrates to function. Some of these cells can use a byproduct of fat called ketones for energy but it's typically insufficient. The body starts breaking down muscle proteins to make glucose (a carbohydrate).

"This is bad, bad, bad," explains Beth Kitchin, MS, RD, and Assistant Professor at the University of Alabama at Birmingham, Department of Nutrition Sciences. "As the fast progresses you will lose muscle mass, and if it continues for a long time, you could lose brain and heart tissue."

Furthermore, because muscle is a big calorie burner and revs the metabolism, fasters losing muscle mass will experience a short-term drop in metabolic rate -- which means less calorie burning. This is exactly the opposite of what a person wants when trying to lose weight, says Kitchin.
Bottom Line
Anyone using a fast for lasting weight loss will be disappointed, says Kitchin. "The weight loss will be mainly water, stored carbohydrates, and muscle mass. So any weight lost will likely be quickly regained." Kitchin also warns that people who fast risk setting themselves up for a cycle of overeating and bingeing due after being in a state of starvation. "I know it sounds like the boring, same old story," says Kitchin, "but the best way to lose weight is slow and steady. That way, you're much more likely to keep it off in the long run."

Bland agrees that fasts are not the best weight-loss methods to employ due to the temporary weight loss and the risk of body imbalances. "Fasts don't teach balanced eating and since they are usually followed for a few days, they don't promote a healthy lifestyle change or long-term health practices," says Bland. The key to weight loss is following a balanced, healthy meal plan with controlled portions, and complemented with regular physical activity."

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