The threats to public health from widespread obesity are well known. So are the main solutions—we all need to move more and eat less. Evidence is still sparse, however, on the effectiveness, and, importantly, the cost effectiveness of large scale public health interventions to prevent and treat obesity. But a fifth of Europe's population is already obese, and obesity in adults accounts for up to 6% of direct health costs and more than 12% in indirect costs of shortened lives, reduced productivity, and lowered incomes.1 Can Europe afford to wait for better evidence? The World Health Organization does not think so.

This month in Istanbul, WHO brought together from all corners of Europe ministers of health; ministers from other sectors such as education, sport, environment, transport, and agriculture; the food industry; public-private partners; and non-governmental organisations with the aim of taking real and immediate action on obesity. The meeting was more than a high level talking shop. The …