What happens when you eat too much fat in ONE day?

I'm quite sure expel means pooping. But as the other person said excess calories will add fat to the body. When I normally eat a very healthy low-fat diet, then splurge for 1 day on fatty foods, the next day I have 'sour-burps', and found that an Alka-seltzer works wonders. Then I vow to not eat like that again.