Fat not found Nature
The vast majority of c-c bonds in all fats are single, aka saturated (no room for more hydrogen side atoms).
If double bonds (unsaturated) present & converted to single bonds by industrial hydrogenation lacking control: ½ cis, ½ trans. All living cells do cis- see google images ancel keys started & marketed the myth, 1953, that sat. Fats of natural origin unhealthy & helped drive this problem.