On a several hour flight such as DTW-LAS or IND-LAX I can easily down half a dozen of whatever happens to strike my fancy that day. Feel free to do the same, assuming you can hold that much liquor. Know your limit and that's all you need to worry about. Don't be "that guy" who got drunk and annoyed the other passengers.

Eat as much as you need from the snack basket, just don't take so much that you are denying to others. There are extra snack basket supplies in the galley so unless you are a serious glutton you aren't in danger of denying to others.