Magic Pill for Dieting? Wait for It on the Treadmill

Summer has long been a time of renewed efforts to lose excess pounds that are hard to hide under skimpy hot-weather clothing. And to be sure, some people (rarely those significantly overweight) manage to shed 5 or even 10 pounds before the Fourth of July.

Skip to next paragraph Stuart Bradford

More Columns: Personal Health Forum: Fitness and Nutrition

But having just driven from New York to Minnesota and back, at every rest stop I saw evidence of what health experts are calling a national crisis - an epidemic of obesity, especially life-limiting, health-robbing morbid obesity.

No doubt most of the extremely overweight people I encountered had tried and ultimately failed to keep their weight under control before tipping the scales at 300-plus. In recent decades, they had hundreds of diets to choose from, and many probably lost an encouraging number of pounds on fleetingly fashionable schemes, only to regain the weight and more when they tired of the diet of the day.

Now some experts are saying that bariatric surgery to shrink the stomach and to bypass part of the intestines is the most effective solution for such people, permitting a loss of half their body weight. But even this radical, risky and costly operation sometimes fails to keep people trim.

Can Medication Help?

Enter - or I should say, re-enter - drugs that promote weight loss. You may recall the many desperate souls who years ago sought to curb their appetites with amphetamines, drugs that caused extreme nervousness, insomnia and addiction. Among other diet drug fiascos were thyroid hormone, which caused hyperthyroidism; fenfluramine, linked to heart valve abnormalities; and ephedra and phenylpropanolamine, associated with heart problems.

Now a host of other medications, several already on the market and others in the pharmaceutical pipeline, are being cited as safer alternatives. However, these too have limitations, and before you ask your physician for a prescription or try to buy the drugs online, you should know just how effective and safe they really are.

In the June issue of The Journal of the American Dietetic Association, Susan B. Moyers of the University of South Florida College of Medicine reviewed drugs that had been studied as weight-loss aids. But before I provide the details, you should know Dr. Moyers's bottom line: "Whereas the evidence may support the use of medications to enhance weight loss, medication alone without diet/lifestyle change is not effective."

In other words, there is no drug currently available or likely to be available soon that facilitates weight loss without also cutting back on calories consumed. And there is no drug that can help people maintain a weight loss unless they continue to limit calories or increase exercise.

Furthermore, there is as yet no drug that enables the morbidly obese, even with a reduced-calorie diet, to lose 100 or more pounds. Typical losses average 5 to 10 percent of initial weight, which can significantly improve health but won't turn the obese into normal-weight individuals.

In the same issue of the dietetic journal, Dr. Frank Greenway, medical director of the Pennington Biomedical Research Center at Louisiana State University, noted that obesity was a chronic disease, not unlike diabetes or high blood pressure, that requires continuing treatment.

"No one expects a person with hypertension to maintain a normal blood pressure if he stops his medication, but there is still a bias that medication for treatment of obesity should be time-limited," he wrote.

But medical insurance rarely covers the cost, which can exceed 0 a month. In addition, side effects of the drugs prompt many people to stop taking them.

The two leading prescription weight-loss aids are Meridia (sibutramine) and Xenical (orlistat). Meridia acts on the brain to reduce hunger and enhance satiety. It reduces between-meal snacking and limits the drop in metabolic rate that accompanies weight loss.

Typical weight losses of 5 to 10 percent (10 to 14 pounds in six months) have been reported. The drug should not be used by those with a history of heart disease or stroke or people who take antidepressants called MAO inhibitors or S.S.R.I.'s.

Xenical interferes with the enzyme that digests fat and can reduce by a third the amount of dietary fat a person absorbs. In a large four-year study, one quarter of patients who stayed on the drug kept off 10 percent of their initial body weight (about 13 pounds in a year), compared with 16 percent of patients on a placebo. Xenical is not a drug for fat lovers. If more than 20 grams of fat a day are consumed, the drug can cause oily stools, flatus with discharge and fecal urgency. It also interferes with the absorption of fat-soluble vitamins.

12Next Page >

Jane E. Brody can be reached at personalhealth@nytimes.com.