Why can we get up for a piece of chocolate, but never because we fancy a carrot? Research has demonstrated part of the answer: triglycerides, fatty substances from food, may act in our brains directly on the reward circuit, the same circuit that is involved in drug addiction. These results show a strong link in mice between fluctuations in triglyceride concentration and brain reward development. Identifying the action of nutritional lipids on motivation and the search for pleasure in dietary intake will help us better understand the causes of some compulsive behaviors and obesity.