Claim: Nathan Pritikin created a dietary and exercise regime called the Pritikin Diet (described as "nutritionally adequate" by gastroenterologist David Hershel Alpers) that entailed consuming more vegetables, fruits, beans, and whole grains, and only small amounts of meat/dietary products, along with aerobic exercise.
Evidence: Based on studies indicating that people in primitive cultures with primarily vegetarian lifestyles had little history of heart disease and western cancers, and medical data available during WW2 detailing rates of disease in various countries he created a low-fat diet that was high in unrefined carbohydrates like vegetables, fruits, beans, whole grains, small amounts of meat/dairy products along with a moderate aerobic exercise regime. His dietary and exercise regime is called the Pritikin Diet. Gastroenterologist David Hershel Alpers and colleagues described the Pritikin diet as "nutritionally adequate, but the low fat content makes it unpalatable, and the likelihood of compliance is low."