Silencing Scer\GAL4^Mip.PM neurons significantly increases body weight (BW) (by 20-30% compared to controls) and leads to enlarged abdomens (with denser layers of fat body cells) in male and female flies. BW increase is apparent 1 day after eclosion, peaks at 5-10 days and then stabilizes. There is no difference in body or wing length shortly after eclosion, compared to controls. Temporal silencing in the adult (using Scer\GAL80^ts.αTub84B) is sufficient to increase BW. Flies with silenced neurons eat twice as much as controls and survive twice longer than controls without food; the BW phenotype is only evident in ad libitum but not restricted feeding conditions. Activating Scer\GAL4^Mip.PM neurons show significant BW loss and leaner abdomens with less fat tissue in males and females (around 30% compared to controls). Before Scer\GAL4^Mip.PM neuron activation, flies eat the same amount as controls; upon activation, flies eat 70% less food than controls; after ending activation, flies show a feeding rebound (eating 70% more than controls). Silencing Scer\GAL4^Mip.PM neurons in the presence of suppresses increases in BW phenotypes. Activating Scer\GAL4^Mip.PM neurons leads to decreased BW, but no change in BW is seen with the additional presence of Mip¹/Mip¹; presence of Df(1)Exel6234 in flies with activated Scer\GAL4^Mip.PM neurons still show decreases in BW. Silencing Scer\GAL4^Mip.PM neurons significantly increases attraction to food odors (whereas activating neurons significantly decreases attraction) compared to controls. Satiated flies with silenced Scer\GAL4^Mip.PM neurons show significant increases in proboscis extension response (PER, to sucrose solution) compared to controls, as if they were starved; this effect is not present if the flies are starved for 18hrs. Activating Scer\GAL4^Mip.PM neurons leads to significant decreases in PER (after 18hr starvation) compared to controls. Flies with silenced Scer\GAL4^Mip.PM neurons have significantly more sensitive ab3A olfactory receptor neuron responses to ethyl butyrate than controls, and flies are hyperphagic on sweet (but not non-sweet) substances. Scer\GAL80^ChAT.7.4P suppresses increases in body weight seen in male and female flies with silenced Scer\GAL4^Mip.PM neurons.