The fat content is similar in both cow and soy milk, and low fat or “light” varieties are available for both. The type of fat in full-cream cow’s milk is butterfat, high in saturated fat, while soybean oil is mostly polyunsaturated. The fats added to soy milk are usually canola or sunflower oil, again rich in polyunsaturated and monounsaturated fats. This means that soy milk is a source of “good” fats.