Nonprescription diet aids proliferate so quickly—the names of the products and their makers changing so frequently—that no oversight agency, no matter how efficient, can keep track of them. The Internet has made their sale all the easier (a quick search for any diet supplement on the Web pops up scores of vendors eager to dole out bottles of the stuff at the click of a mouse). As a result, consumers are left largely on their own. But understanding a few basic principles helps:  

• Virtually all weight-loss supplements, even moderately effective ones, contain either amphetamine-like herbs or laxatives.
• Amphetamines speed the heart and nervous system, tend to aggravate rather than mitigate high blood pressure and other side effects of being overweight, and can be addictive.
• Laxatives—potentially dehydrating, particularly in children—can also be addictive.
• Both amphetamines and laxatives tend to lose their power over time, forcing users to raise the dose, often to dangerous levels.

Controlling appetite is a complicated process, one that has yet to be fully understood by scientists. The labyrinth of genes, proteins and hormones regulating our eating behavior is dense, byzantine and extremely difficult to fool or manipulate. Knocking out one or two components of this system with supplements—or even prescription drugs—is unlikely to work for long because other components rush in to take their place. At best, the prescription weight-loss drugs that are currently available, as well as those in the pipeline, are considered a stopgap measure, a crutch to support patients as they develop healthier life strategies.

Before purchasing a diet supplement, consider this: Were the scores of over-the-counter weight-loss remedies safe and effective, they wouldn't rely for sales on Sunday morning infomercials and endorsements from trumped-up diet experts. Given that obesity and overweight are among the most common 21st-century ills, any product that actually helped people to get thin quickly, safely and with minimum effort would sell itself. Thanks to the tragic loss of a young ballplayer, Congress is finally stepping up to the plate in an effort to regulate diet supplements. But for now, prudence and common sense are our best protection: Rather than throw your money away on worthless and possibly dangerous over-the-counter diet aids, consider sending a note to your congressperson demanding their regulation.  

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