A public health approach to the problem of obesity.

Overweight and obesity have an underestimated impact on public health and therefore on national economic costs. The rising prevalence of overweight and obesity is inextricably linked to the increase in the average BMI and its population distribution. English activity patterns have probably fallen over 20 years by an average of 800 kcal/day; the remarkable changes in eating patterns reflect the pervasive physiological suppression of intake by about 750 kcal/d. The resulting small positive energy balance explains the secular increase in average adult weight. Similar changes and discrepancies occur with aging. Together these changes can explain the accelerating skewness of BMI distribution and particular propensity of women to obesity. The genetically susceptible probably dominate the upper BMI range and seem to reflect subtle discrepancies in energy balance in an inactive society on a high fat diet. Maternal programming of gene expression in utero may amplify intergenerational increases in weight but also amplify a stress-mediated susceptibility to abdominal obesity. The needed transformation in thinking on transport, environment, work facilities, education, health and food policies and perhaps in social and economic policies is unlikely when governments are wedded to individualism but without these changes to enhance physical activity and alter food quality societies are doomed to escalating obesity rates.