The Skinny on Fat
Rodgers, Katie, Drug Topics
The search for a cure for obesity accelerates
Approximately 58 million adults-one-third of the U.S. population-are overweight, according to the latest U.S. Census Bureau data. In 1990, 32.4% of Americans were obese, up from 25% in 1980. More than just a matter of appearance, obesity can cause cardiovascular disease, hypertension, noninsulindependent diabetes mellitus, high cholesterol levels, and other serious health problems (see box on page 87).
Obesity is taking a hit on Americans' wallets, too. Decision Resources, a market research company in Waltham, Mass., reports that obesity and its complications add approximately $100 billion a year to our health-care tab. One-third of that total is spent on consumer weight-loss products and services.
America's weight problem has not gone unnoticed, and, as part of its "Healthy People 2000" program, the U.S. Department of Health & Human Services set a goal of reducing the prevalence of overweight to no more than 20% among people aged 20 and over and no more than 15% among adolescents aged 12 through 19.
Barbara Hansen, Ph.D., professor of physiology and director of the Obesity & Diabetes Research Center at the University of Maryland School of Medicine, is pessimistic about the ability of Americans to achieve the Healthy People 2000 goal. "It's not even remotely possible, because over the past two years, we've been increasing the prevalence of obesity, not decreasing it," she said. "We're already in the gaining mode instead of the losing mode." Hansen said scientists are at a loss to explain why Americans are gaining weight, especially since they are consuming less fat in their diets.
According to Hansen, the underlying question in obesity research is, What causes obesity? "Once you know what causes it, you might have some idea about why it's difficult to treat it or reverse it," she said. "As far as we know, a great deal of excess fat is a genetically determined fact of life. That's not to say that diet and exercise can't influence it. But, generally, the largest component is probably genetic, and we are attempting through our behavioral means to alter something that's genetically present."
Hansen pointed out that, although most people succeed in losing weight on various diet programs, the problem is that most folks gain it back. "That's probably because [losing it] did not fix the underlying problemwhatever that problem is," she said.
"Those very few who have maintained [their weight loss] have done so only with extraordinary vigilance," Hansen stated. "That's because whatever those mechanisms are underlying body weight control, we have not found a way to alter them." In treating obesity, "we are essentially using behavior to overcome physiology, and that's very difficult to do over a long period of time," she said. "You can do it for a short time, but not for a long time."
Antiobesity drugs, or anorectics, are used to make dieting a little bit easier and are meant to be used in conjunction with a diet and exercise routine. When selecting drugs to treat obesity, physicians have a limited menu from which to choose. Most available agents affect dopamine, norepinephrine, or serotonin, neurotransmitters that affect the transmission of satiety signals.
The majority of agents available by prescription are sympathomimetic amines, and because they are chemically related to amphetamine are classified as controlled substances under federal law. In some states, further restrictions have been put on their use because of concerns about the misuse, abuse, and addiction potential of anorectics. In Tennessee, for example, physicians are prohibited from prescribing and pharmacists are prohibited from dispensing "amphetamine-type" drugs for the treatment of obesity. Massachusetts recently amended its law, which prohibited the prescribing of "any drug, including but not limited to amphetamines and sympathomimetic amines, for its anorectic effect. …