Food choice is under the control of at least two interconnected brain systems. The homeostatic systems of the hypothalamus and caudal brainstem, under the influence of leptin, insulin, ghrelin and other signals from the periphery, ensure that our overall intake of calories and nutrients balances energy expenditure to maintain a stable body weight. The hedonic, or reward, system of limbic brain areas drives the motivation to preferentially consume more palatable and energy-dense foods. The reward system has thus been suggested to underlie overeating, hence contributing to the obesity epidemic. Palatable foods activate opioid and cannabinoid pathways in the brain’s reward system, so it is natural to speculate whether certain foods could act like drugs of abuse, even to ask whether such foods could have addictive properties.