Recommendations regarding limiting saturated fats and cholesterol emerged from a series of epidemiological studies in the 1950s, and related American Heart Association dietary guidelines emerged between 1957 and 1961. The 1957 AHA report included: (1) Diet may play an important role in the pathogenesis of atherosclerosis, (2) The fat content and total calories in the diet are probably important factors, (3) The ratio between saturated and unsaturated fat may be the basic determinant, and (4) A wide variety of other factors besides fat, both dietary and non-dietary, may be important. By 1961, these finding had been strengthened, leading to the new 1961 AHA recommendations: (1) Maintain a correct body weight, (2) Engage in moderate exercise, e.g., walking to aid in weight reduction, (3) Reduce intake of total fat, saturated fat, and cholesterol. Increase intake of polyunsaturated fat, (4) Men with a strong family history of atherosclerosis should pay particular attention to diet modification, and (5) Dietary changes should be carried out under medical supervision. These recommendations continued to become more precise from 1957 to 1980, but maintained "a general coherence among them".