Many obese people report losing pleasure in eating rich foods — something also seen in obese mice. Scientists have now discovered the reason. Long-term high-fat diets lower levels of neurotensin in the brain, disrupting the dopamine pleasure network and decreasing the desire to eat high-fat foods. Raising neurotensin levels in mice brings back the pleasure and aids weight loss. Bringing back the pleasure could help people break the habit of overeating.