No Fast Way to Lose Weight

Ash Wednesday, which is tomorrow, is a fast day for many Christians -- who don't, of course, have a lock on this ancient practice. Giving up food, drink or both for a limited time is a part of most major religions.

Brief fasts are also required before many medical procedures to improve accuracy (blood tests for cholesterol and glucose; colonoscopy) or safety (surgery).

For decades, though, fasting has also frequently crept into the weight-loss world, fueled in part by former medical practice. Before the advent of insulin about 80 years ago, fasts were sometimes used to treat people with diabetes, a practice that was both ineffective and dangerous. Doctors also used to hospitalize obese people for extended, medically supervised fasts. Lack of food sometimes caused death from erratic heartbeats until programs added protein and electrolytes such as potassium. Today, the practice is rarely used.

None of that has ended a fascination with fasting for those looking to shed weight quickly. Amazon.com offers 20 pages of books on fasting that range from the basics ("The Complete Idiot's Guide to Fasting") to the risky extreme of going without food for long periods ("Fasting Girls: The History of Anorexia Nervosa").

Brief fasts for religious or medical reasons are generally safe. "But if you have other medical conditions such as diabetes, congestive heart failure, or if you're pregnant or lactating, there's no religion that I know of that permits you to fast if your health is jeopardized," says Arthur Frank, director of the George Washington University Weight Loss Center.

Fasting to purportedly detoxify the body or even to lose weight "is a preposterous way to approach things," notes Steven Heymsfield of the New York Obesity Center at St. Luke's-Roosevelt Hospital. "It's nonsense."

While fasting can cause a quick drop in weight, the loss is deceiving. It comes not from burning fat, but from loss of fluids and glycogen -- a substance that is broken down to glucose.

Fasting "is a double-edged sword," said Lona Sandon, a registered dietitian at the University of Texas Southwestern Medical Center in Dallas and a spokeswoman for the American Dietetics Association. "If you're not eating calories, you will lose weight, but the body also says that 'you're not giving me calories,' so it slows down metabolism. That ends up working against you."

Here's what medical experts say are better options than fasting:

Boost protein. Protein has half the calories of fat, fosters satiety more than carbohydrates and requires more calories to digest than either fat or carbohydrates. At Washington's MedStar Obesity Institute, physician Richard Atkinson offers obese and overweight patients a regimen of up to 35 percent of daily calories as protein, mainly fish, nonfat and lowfat dairy foods and lean poultry and meat. Check with your doctor first if you have kidney or other health problems, Atkinson says.

Space meals out. Doing so is a kind of modified fast, says Frank. "And if you can skip a meal comfortably and it doesn't cause you to compensate by having two bagels and a doughnut a few hours later, then do it," Frank says. "There are lots of people who don't like breakfast and lots of people who comfortably skip lunch. But it's got to be comfortable for you."

Eat more green vegetables. They're extremely low in calories, high in volume and loaded with vitamins and phytonutrients. Atkinson prescribes at least 10 servings, to be eaten at regular intervals throughout the day.

Become more active. Burning more calories is absolutely critical to losing weight and avoiding extra pounds, says Medstar's Atkinson. "With significant exercise -- riding a stationary bike, for example -- we've found that you burn fat for a number of hours afterwards," he says. "But any exercise is better than none. I usually pace on conference calls and can walk at least two miles [while doing so]. That's 200 calories."

-- Sally Squires

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