7/28/2019 ObesityWhat Is done

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8www.sciencemag.org SCIENCE VOL 299 7 FEBRUARY 2003

O B E S I T Y

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

This issue ofScience also reports some of this bad news. We learn, for starters, that the obesityepidemic is recognized by the World Health Organization as one of the top 10 global health prob-lems. Multiple social forces work against maintenance of a healthy weight, such as food availabil-ity, 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. Allof us, particularly certain populations, have powerful genetic predispositions to retain excess calo-ries in preparation for famine. The biological systems that manage our food intakecontrolling howoften and how much we eat and making corrections when the long-term equilibrium is disruptedare extraordinarily complex and not yet well understood. Powerful biological control mechanismsspur calorie intake, but less powerful ones limit it. As-yet-unknown players are probably confound-ing researchers efforts to untangle this system. Clinicians have few tools with which to fight thisepidemic; 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 againstthis epidemic. The tools of molecular genetics have yielded a rush of new information about molecu-lar 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 theNews story by Marx, p. 846). Informationfrom basic research has identified numerousdrug targets, as Guras News story (p. 849)

points out. Several compounds are in humanclinical trials now, and more are in develop-

ment. Although Friedman (p. 856) outlinesthe enormity of the obesity problem in hisViewpoint, likening it to that of cancer, hesuggests that new molecular knowledge cou-

pled with an evolutionary view may give usenough information to fight obesity produc-tively. Science clearly has the potential to in-form and perhaps help solve some aspects ofthis intricate problem. What about socialforces? Hill et al. (p. 853) argue in their View-

point that it will take only a small reduction in daily net energy input to pre-vent further increases in obesity ratesan attainable goal, they believe. So-cial change can also occur in the medical profession as physicians and oth-er 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 distri-bution of food and its advertisement (with the goal of maximizing food con-sumption) conflict with the public good, who is to intervene and how?

KATRINA KELNER AND LAURA HELMUTH

ObesityWhat Is

To Be Done?

T I T L E O F S P E C I A L S E C T I O N

I NTRODUCT ION

CONTENTS

N E W S

8 4 6Cellular Warriors at the Battleof the Bulge

8 4 9 Obesity Drug Pipeline Not So FatHaving It All

V I E W P O I N T S

8 5 3 Obesity and the Environment:Where Do We Go from Here?

J. O. Hill et al.

8 5 6 A War on Obesity, Not theObese

J. M. Friedman

8 5 9 A Clinical View of the ObesityProblem

X. Pi-Sunyer

Related editorial on page 781 andScience's STKE on page 775.

P A G E

8 4 9

CREDIT:FRANCISG.MAYER/CORBIS