The researchers used the drug bromocriptine (a D2R agonist) to simulate higher dopamine levels. Insulin sensitivity and fat oxidation improved.
Body weight did not improve during the time of the study, but improved insulin sensitivity and fat oxidation rates should improve body composition over time (the study only lasted 8 days). Resting energy expenditure was also increased by about 50 calories a day.
Dopamine is a neurotransmitter associated with ambition and reward. Higher dopamine levels also reduce appetite.