What is the cause of rapid weight gain on actos (pioglitazone) an anti diabetes medicine?

Acots side effects: Weight gain is a known side effect of Actos (pioglitazone). The good news is that Actos is very effective in reducing visceral fat (fat in the abdomen) which is associated with increased risk for cardiovascular disease. The weight gain from Actos is peripheral and does not carry the same risk as visceral fat. As always watching calorie intake and activity to loose weight is key.