Obesity--What Is To Be Done?

The word epidemic conjures up alarming images: plague, pestilence, destruction, and death. We are not used to lumping obesity in with such disasters, but the recent increase in the global prevalence of obesity qualifies as an epidemic. Obesity claims an increasing number of lives worldwide; discouraging statistics abound in both the medical and popular press.

This issue of Science also reports some of this bad news. We learn, for starters, that the obesity epidemic is recognized by the World Health Organization as one of the top 10 global health problems. Multiple social forces work against maintenance of a healthy weight, such as food availability, declines in traditional lifestyles, and sedentary living. The medical profession is reported to lack both the knowledge and the incentives (financial and otherwise) to combat this threat to health. All of us, particularly certain populations, have powerful genetic predispositions to retain excess calories in preparation for famine. The biological systems that manage our food intake--controlling how often and how much we eat and making corrections when the long-term equilibrium is disrupted--are extraordinarily complex and not yet well understood. Powerful biological control mechanisms spur calorie intake, but less powerful ones limit it. As-yet-unknown players are probably confounding researchers' efforts to untangle this system. Clinicians have few tools with which to fight this epidemic; current antiobesity drugs are not highly effective and are fraught with side effects.

But the articles in this issue also point to areas where we can expect to make real progress against this epidemic. The tools of molecular genetics have yielded a rush of new information about molecular signals that guide short-term decisions, such as whether to eat now or push away from the table. Other molecules take a longer view, monitoring fat balance (see the News story by Marx, p. 846). Information from basic research has identified numerous drug targets, as Gura's News story (p. 849) points out. Several compounds are in human clinical trials now, and more are in development. Although Friedman (p. 856) outlines the enormity of the obesity problem in his Viewpoint, likening it to that of cancer, he suggests that new molecular knowledge coupled with an evolutionary view may give us enough information to fight obesity productively. Science clearly has the potential to inform and perhaps help solve some aspects of this intricate problem. What about social forces? Hill et al. (p. 853) argue in their Viewpoint that it will take only a small reduction in daily net energy input to prevent further increases in obesity rates--an attainable goal, they believe. Social change can also occur in the medical profession as physicians and other health care professionals learn more about how to treat obesity, as argued by Pi-Sunyer (p. 859).

Perhaps the biggest challenge is outlined by Nestle in her editorial (p. 781). When the interests of corporate institutions that control the distribution of food and its advertisement (with the goal of maximizing food consumption) conflict with the public good, who is to intervene and how?