All fats are not same. Some fat may be bad for us, but our bodies need some fat from food because it’s one of the major sources of energy. It helps us absorb some vitamins and minerals. Fat is crucial in building cell membranes, the vital exterior of a cell. Fat is essential for muscle movement, blood clotting, and inflammation.
For long-term health, some fat is good, and other not so much. Good fats are monounsaturated and polyunsaturated fats. Bad ones include man-made industrial trans fats. Saturated fats are somewhere in the middle.
The worst type of fat is known as trans fat. It is a byproduct of hydrogenation, which is used to turn liquid oils into solids and to prevent them from becoming rancid.
When vegetable oil is heated in the presence of hydrogen and a heavy-metal catalyst, the process turns oils into solids. It makes healthy vegetable oils to the bad saturated fats. On the ingredient lists, this substance is usually called as “partially hydrogenated oil”. Try staying away from at as much as possible.
Source: Harvard Health Publishing