| Abstract: | Objective: Rapid synaptic dopamine transport or reduced brain dopamine receptor signaling may influence energy intake. Methylphenidate, a dopamine reuptake inhibitor, increases brain synaptic dopamine and produces anorexia, suggesting that it may reduce energy intake. We investigated the effects of two doses of short‐acting methylphenidate on energy intake over one meal in obese adult males. Research Methods and Procedures: Nine obese males (>85th BMI percentile) ingested a placebo or a moderate dose (0.5 mg/kg) or a high dose (1.0 mg/kg) of methylphenidate in a within‐subject double‐blind acute laboratory study. One hour after ingestion, pizza consumption was measured in a naturalistic laboratory setting. Results: Participants reduced energy intake by 23% for the moderate dose vs. the placebo (p < 0.02), but there was no significant difference for the high dose vs. the moderate dose (p > 0.05). Participants consumed 34% fewer kilocalories after ingesting the lowest effective dose of methylphenidate compared with placebo (725.7 ± 404.5 vs.1095 ± 271.1 kcal, p < 0.01). Seven of nine subjects responded to the moderate dose. The increase in perceived drug effect above placebo was correlated with the reduction in energy intake for both the moderate (r = ?0.85, p = 0.004) and the high (r = ?0.75 p = 0.021) doses. Hunger scores were not different across drug doses or placebo before drug administration. Discussion: Methylphenidate reduced energy intake of a highly palatable food over one meal by one‐third in obese adult males. Dopamine transport inhibition may be an effective component of a comprehensive treatment for obesity. |
