OLESTRA is a fat replacer used in food processing that can bind to fat soluble vitamins and thereby reduce their absorption. As a fat substitute, olestra does not add fat, calories or cholesterol to products. It is normally used in the preparation of high fat foods in order to lower their fat contents.
Reasoning - As ice age and resistant of water became changing in ponds and lake the resource of food started to deplete so evolution became a evolving for creatures aka reptiles.