Food fats can be of animal or vegetable origin. The first ones also called "saturated fatty-acids" are the ones found in meat, or in foods of animal origin, such as butter, margarine, lard. At room temperature they are solid, dense, heavy and difficult to digest.
The second ones are also called "unsaturated fatty-acids" and are of vegetable origin, such as olive and seed oils. At room temperature they are liquid, light and easier to digest.

It is better not to eat too many saturated fats, If ingested in great quantity they may provoke an increase in the cholesterol level and tryglicerides in the blood, responsible for diseases such as hypertension.
Try to favour "unsaturated" fats, the ones of vegetable origin, because they tend to decrease the cholesterol level. It is also important to remember that the unsaturated fatty-acids can carry out their useful function in the organism only in the presence of vitamin E.