Your body can only digest so much fat at once, and if you eat too much, most of it just passes through.

Your body can only absorb as much fat as your bile can handle. If you eat more fat than your bile can process, the extra fat just passes right through you and comes out in your stool.

Eating a lot of animal fat makes your body excrete much more bile acid into your stool. This matters because too much bile acid in the colon is thought to increase the risk of developing bowel cancer.