Never Say Diet? : Exercise the Key

by Food and Drug Administration (FDA)

(Page 3 of 3)

Rather than severely restricting caloric intake and depressing metabolic activity as a result, weight-loss specialists now advise moderate exercise as a means of achieving weight control. "A person not only burns calories while exercising, but if he or she is eating an adequate amount of food, calories will continue to be burned at a higher rate for up to several hours afterward," says Callaway.

"For most people, cutting fat intake and adding moderate exercise can work as well as a commercial weight control program," says Pi-Sunyer. Exercisers are also more likely than sedentary people to keep weight off, whether they use a "do-it-yourself" diet or attend a program.

Unfortunately, weight maintenance is a universal failing of all weight-loss programs, regardless of how expensive or well-established. "If you're going to evaluate weight-loss success, you can't just look at the number of pounds lost. You have to look at long-term weight maintenance," says Callaway.

"Diet programs make money on the weight-loss phase, not the weight maintenance phase. At the time when people need the most help in controlling their weight, many programs cut them off," says Pi-Sunyer. By various estimates, as many as 85 percent of dieters put the weight back on within two years after weight loss.

"Perhaps weight-loss programs should be less focused on weight control and more focused on identifying individual risk factors and dietary patterns associated with obesity, and to modify them where possible," suggests Glinsmann.

"Obesity is not yet well understood," concedes Pi-Sunyer, "and all we can do right now is to tell people to exercise and to cut down on fat intake." However, while genetic predisposition towards obesity can be mitigated by exercise and sensible eating habits, some people will have to work a lot harder at keeping weight at optimal levels than others. "It's like jazz — there's a theme and rhythm and you've got to work within that framework, but you can improvise," says Callaway.

Product Bans and Controversies

In the wake of last year's House Committee on Small Business hearings on the $33 billion weight-loss industry, FDA and the Federal Trade Commission separately announced investigations into the safety and efficacy of diet pills and programs, and how they are promoted in advertising. FDA also moved to pull dangerous or ineffective products off store shelves.

In the fall of 1990, FDA proposed a ban on 111 ingredients in over-the-counter (OTC) diet products, including amino acids, cellulose, grapefruit extract, and kelp. The agency had given manufacturers of these products an opportunity to provide data from clinical tests showing they were effective in promoting weight loss, but did not receive adequate information to support advertising claims, according to William Gilbertson, Pharm.D., director of FDA's OTC Drug Review Program. "Many of these ingredients had been marketed before 1962 [when an amendment to the 1938 Food, Drug, and Cosmetic Act was passed requiring drugs not only to be safe, but also effective] and had never been evaluated for efficacy," Gilbertson explains.

He says that manufacturers wanting to market weight-loss drugs using the banned ingredients will have to get prior FDA approval — which means filing a new drug application and supplying data from clinical tests to support claims.

FDA also recalled Cal-Ban 3000, a heavily advertised diet pill containing guar gum (a vegetable gum that swells when it absorbs moisture, providing a feeling of fullness, according to advertising claims) after receiving a number of consumer complaints of adverse reactions. In a number of cases, the tablet caused gastric or esophageal obstruction, and one person died as a result of complications following surgery to remove the mass of gum blocking his throat.

The most widely used ingredient in OTC diet pills, phenylpropanolamine hydrochloride (PPA), an appetite suppressant that is chemically related to amphetamines, has been the subject of a decade-long medical dispute. Though clinical tests yielded conflicting results (often due to defects in study design), an FDA panel concluded in 1982 that enough data existed to support the efficacy of PPA in curbing the appetite to qualify it as an OTC weight-loss aid. However, a controversy developed over PPA's safety. The drug can cause small elevations of blood pressure at recommended doses and there are a few reports of marked blood pressure elevation and intracranial bleeding associated with its use. Whether such events are truly drug-related and can occur at recommended doses is the subject of debate.

In May, FDA held a public meeting to explore such issues as whether PPA can cause such central nervous system damage as stroke when taken at (or over) the recommended dosage, whether the drug poses a health hazard to teenagers, and whether PPA is especially hazardous to those with eating disorders.

For its part, FTC has begun to look into advertising claims of 14 diet programs. "We are concerned with programs that go beyond promising weight loss and claim to be able to keep the weight off," says Richard Kelly, assistant director of FTC's division of service industry practices. Additionally, FTC is looking into whether diet companies are touting the safety of their programs while playing down such health risks as the development of gallstones or loss of muscle tissue. Kelly expects the FTC investigation to be completed by the end of the year.

FTC also monitors advertising claims for diet aids on an ongoing basis and takes legal action to get companies to stop making unfounded claims. Among the agency's recent targets: Fat-Magnet, a pill that claimed to break up into thousands of tiny "fat-attracting" particles that "flush" fat from the body, and FibreTrim, a high-fiber supplement that its manufacturer claimed could aid in weight reduction.

FDA's ban of ineffective diet drugs could make future FTC action easier. "The FDA says these products are not efficacious, which is a good piece of evidence to have when we go to trial," says Judy Wilkenfeld, assistant director of FTC's advertising practices division.

Consumers can get a list of ineffective diet aids by writing to: FDA, HFE-40, 5600 Fishers Lane, Rockville, MD 20857.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.