Overweight and obese Americans may soon have easy access to orlistat (sold as Alli), a drug that has been shown to be helpful to those trying to lose weight and improve their health. An advisory committee to the Food and Drug Administration (FDA) has recommended approval of GlaxoSmithKline's application to sell orlistat over the counter (OTC), that is, without requiring a doctor's prescription. While the FDA doesn't have to follow advisory committees' recommendations, it usually does so.
Obesity -- excess body fat -- is one of the most difficult chronic health conditions to ameliorate. Its prevalence in the United States has increased substantially over the last few decades, and public health experts fear that the many obesity-associated health conditions (such as diabetes, hypertension, and coronary heart disease) will overwhelm the health care system.
Obesity is basically a condition of energy imbalance, resulting from more calories consumed than are burned by activity. Thus, it seems straightforward to treat it by reducing calories consumed and/or by increasing activity, but that's easier said than done. For example, one way to reduce the number of calories consumed is to reduce dietary fat, since fat provides more than twice the calories of an equal amount of protein or carbohydrates. Orlistat can help people achieve this aim. The drug prevents the body from breaking down and absorbing all the fat consumed and thus decreases the number of calories actually absorbed into the body.
Orlistat has been available by prescription (as Xenical) since 1999, but neither it nor any other FDA-approved weight loss aid has thus far been sold OTC. The version of orlistat now under consideration would contain half the dosage of the prescription variety (60 mgm as opposed to 120 mgm per pill) and would be taken with each meal.
Like all other effective medications, orlistat is not risk-free. Because the drug decreases fat absorption, it has the potential to decrease absorption of the fat-soluble vitamins (vitamins A, D, E, and K), so people who use it should also take supplements of these vitamins. It can also affect the function of some immunosuppressant drugs and the "blood-thinner" coumadin, so people who use such medications should avoid orlistat or at best use it only under a physician's direction.
Since orlistat blocks the absorption of about 30% of the fat consumed, the more fat one consumes, the more will be excreted. Therefore, if the diet contains a large amount of fat, this may produce unpleasant side effects such as flatulence and diarrhea. Such effects should be a warning to users to decrease the amount of fat they consume -- which in turn should decrease their caloric consumption. These caveats will be noted on the labeling proposed by the manufacturer.
Orlistat alone will not solve the problem of obesity in America -- it's designed to be used in conjunction with a reduced-calorie diet that is low in fat. When used appropriately, however, it can be a useful tool that helps people decrease their fat intake, learn which dietary components provide the most fat and calories, and help them design a more appropriate and healthful diet.
Ruth Kava, Ph.D., R.D., is Director of Nutrition at the American Council on Science and Health (ACSH.org, HealthFactsAndFears.com).