As the prevalence of obesity is rising in the population the average energy consumption is falling. It is clear that the missing link is the amount of energy expended. The current recommendations for minimum energy expenditure are 30 min of moderate exercise, such as brisk walking, five times a week, but many people, especially middle-aged and older women, take little or no exercise. A recent Effective Health Care review on the treatment of obesity concluded that a combination of diet and exercise was more beneficial than diet alone. A systematic review of trials of physical activity promotion concluded that interventions encouraging moderate rather than vigorous intensity exercise, that could be done without recourse to special exercise facilities, were the most likely to succeed. The currently popular `Prescription for Exercise' schemes in the UK have had, at best, limited success. However, evidence is emerging from recent trials of physical activity promotion of new ways to improve initial attendance and long-term uptake of physical activity.