Nathan Pritikin was a college dropout who became an entrepreneur. While doing research for the government during World War II, he observed that populations that had extremely limited food availability because of the war had substantially reduced mortality from cardiovascular disease—something unexpected at a time when cardiovascular disease was thought to be due to stress. 

After the war when food became more available CVD death rates went back up, resulting in Pritikin concluding that CVD was related to diet. Pritikin devised his own very low-fat diet that bears his name and the diet is still in use 65 years later.