Mainly, they make you more hungry.

I used to take Neurontin in the evening after I thought I was through eating for the day. An hour after taking the med, I'ld have an irresistible urge to hit the kitchen looking for something hearty to eat.

I tried waiting and only taking it just as I was getting into bed. Always, I would end up getting back out of bed to go eat something.

I went off this med because of the excessive eating. Then my appetite went back to normal.