On the other hand, population-based studies have found that fat intakes ranging from 20 to 40 percent of calories are not related to breast cancer. The group did agree on the issue of polyunsaturated fats. There is some concern that polyunsaturated fats could increase the risk of breast cancer, and it is consequently recommended that the intake of polyunsaturated fats not go above 10 percent of calories. With regard to dietary fat and obesity, the group was sharply divided due to conflicting evidence. Short-term human studies show overfeeding fat causes fat deposition, while overfeeding carbohydrates has less of this effect.
Epidemiologic studies show no association between fat intake and body fatness.
As for heart disease, the group had three conclusions. First, the combinations of a low-fat diet, weight loss, and regular exercise decreases coronary artery narrowing. Second, there is no adequate study of the impact of low-fat diets on heart attack risk. The group did reach a consensus with regard to an overall dietary pattern. The group said increasing scientific evidence supports diets high in fruits, vegetables, legumes, and whole grains, and which include fish, nuts, and low-fat dairy products.