This report issues a call for urgent action to combat the growing epidemic of obesity, which now affects developing and industrialized countries alike. Adopting a public health approach, the report responds to both the enormity of health problems associated with obesity and the notorious difficulty of treating this complex, multifactorial disease. With these problems in mind, the report aims to help policy-makers introduce strategies for prevention and management that have the greatest chance of success. The importance of prevention as the most sensible strategy in developing countries, where obesity coexists with undernutrition, is repeatedly emphasized. Recommended lines of action, which reflect the consensus reached by 25 leading authorities, are based on a critical review of current scientific knowledge about the causes of obesity in both individuals and populations. While all causes are considered, major attention is given to behavioural and societal changes that have increased the energy density of diets, overwhelmed sophisticated regulatory systems that control appetite and maintain energy balance, and reduced physical activity. Specific topics discussed range from the importance of fat content in the food supply as a cause of population-wide obesity, through misconceptions about obesity held by both the medical profession and the public, to strategies for dealing with the alarming prevalence of obesity in children. "... the volume is clearly written, and carries a wealth of summary information that is likely to be invaluable for anyone interested in the public health aspects of obesity and fatness, be they students, practitioner or researcher." - Journal of Biosocial Science