Dietary behaviour is strongly influenced by the dietary environment, shaped by food supplies, investment policies and advertising, to create an obesogenic food market. Substantial resources have been invested in the production of meat, dairy, oils and sugar and the withdrawal from sale of fruit, vegetables and fish. The result is an ‘obesogenic economy’, i.e. a market economy that encourages weight gain, in which children are a prime target. Interventions in the obesogenic market need to be considered and several opportunities are described in the this paper. Recent moves to strengthen national and international food policies aimed to promote healthier behaviour have been undertaken, but they will need political support if they are to be fully implemented. Alliances of public health interests can help to create that political support and promote health-enhancing environments.