In the late 1950s, Nathan Pritikin was diagnosed with heart disease. Soon after, he adopted a low-fat, high-fiber diet and began a moderate exercise program. Subsequent medical examinations revealed dramatic improvements in his health. Mr. Pritikin developed the Pritikin Diet Program based on his experience and opened the first Pritikin Longevity Center in 1976 so that he could help other people with similar medical problems restore their health.

The Pritikin Diet is almost completely vegetarian, and encourages the consumption of large amounts of whole grains and vegetables. It is high in fiber, low in cholesterol, and extremely low in saturated fat and total fat, containing less than 10 percent of total daily calories from fat. Individuals following the diet are encouraged to eat six or seven meals each day, and are not required to restrict portion sizes. The diet excludes nearly all processed grains and sources of animal protein. In addition to these dietary recommendations, the Pritikin Diet Program includes regular exercise. Program participants are required to walk for at least 45 minutes each day.