Why Not That?

Leviticus 7:22 The Lord spoke to Moses, saying, 23 “Speak to the people of Israel, saying, You shall eat no fat, of ox or sheep or goat. 24 The fat of an animal that dies of itself and the fat of one that is torn by beasts may be put to any other use, but on no account shall you eat it. 25 For every person who eats of the fat of an animal of which a food offering may be made to the Lord shall be cut off from his people. 26 Moreover, you shall eat no blood whatever, whether of fowl or of animal, in any of your dwelling places. 27 Whoever eats any blood, that person shall be cut off from his people.”

The reference here is back to the peace offering, detailed in chapter 3, which was for reconciliation and fellowship between God and a sincere worshipper.  Nothing was to be held back for oneself but totally offered to God. In no cases was the blood to be eaten/drunk, as "the life is in the blood", and many pagan rituals involved the drinking of blood. We see here that even animals that died not from sacrifice but were potentially sacrifices were to be treated the same way.  No sacrifice was to be taken lightly or made for any selfish reasons.  All was Holy to the Lord.