Unlike the burnt offering which was totally consumed, only some parts of the animal were presented as the peace offering on the altar. This included the fat (ḥělěḇ) portions of the intestines (Leviticus 3:3), the kidneys, and fat associated with the hind legs (Leviticus 3:4).
3 And from the sacrifice of the peace offering, as a food offering to the LORD, he shall offer the fat covering the entrails and all the fat that is on the entrails,