On bad ideas*

Could someone please explain:

When I'm completely sober and haven't eaten, I can barely touch kebab. But after having one two seven drinks and a formal hall dinner I can finish a whole chips and cheese with chicken. Why?????**


*Title stolen from Mark, with apologies. Although my post is on a completely different subject, so I guess it's OK.
**This is actually a rhetorical question. I'd rather not think about the answer. ;)