Trans fat is cheap and can withstand multiple heating without breaking down. 
 Explanation: 
-  Trans fat is made by adding hydrogen to unsaturated fats, that is hydrogen is introduced to vegetable oils .
- Big oil companies also spread that it is easily digestible, can be used. multiple times, etc 
- Trans fat was cheap compared to animal fats in the market .
- Using trans fat instead of butter made a lot of sense to them.