Fats stimulate the bile production which in turn enhances the efficiency of digestion process. Moreover, fats also work as lubricant of bowel. If you comes under normal weight category you can take some butter, ghee and vegetable oil. Try to avoid deep fried fatty foods. If you falls in obese or overweight category, be cautious about the type of fat you are consuming. Use vegetable oils (which are rich in unsaturated fatty acids) like olive and safflower in your daily meal preparations.