Eating/sleeping Problem.

Do you smoke before going to sleep? usually that is one thing that would keep you up.
As for drinking, that's odd, puts me to sleep all the time and I am a harsh insomniac.
Like it was mentioned metabolism could be the issue here. Some could eat a little and gain a lot of weight, some need to eat a lot just to maintain theirs.

 

The Nicotine in your ciggs is a stimulant which could keep you awake all night, especially if your smoking 35-40 a day. Also Nicotine is an appetite suppresant