Dr. McDougall began practicing medicine on the big island of Hawaii where extended families were the norm. He treated people who worked on sugar plantations, mostly ethnic Chinese, Japanese, Korean and Filipino. It was not uncommon for him to closely observe three and sometimes four generations within the same family. He got to know many of these families, treating the children, parents, grandparents and sometimes even the great-grandparents of a single family.
At the outset of his medical career, Dr. McDougall was not the least bit interested in diet and nutrition. His medical training had included nothing about it and, consequently, initially he considered the subject irrelevant to health. But as he practiced medicine in Hawaii he observed a rather startling phenomenon that changed the direction of his life: the older generations were in exceedingly good health even after they were well into their eighth, ninth and tenth decades of life. Their health contrasted remarkably with their children and, even more so, with their grandchildren. The younger the patient the more likely they were to suffer from gout, high blood pressure, heart disease, diabetes, colon cancer and obesity.
When Dr. McDougall looked more closely at his patients, he found that they had a lot in common. They all had physically demanding work and they observed many of the same customs. The single greatest difference between the older and younger generations was their diet.
The older patients followed the traditional diets of their ancestors. Their regimens were based primarily on plant foods: grains (like rice), fresh vegetables, beans and fruit. The younger generation had modern diets based primarily on animal foods. They also ate enormous quantities of processed and refined foods that were loaded with fat, sugar, salt and artificial ingredients. If genes were the cause of disease, then why wasn’t the younger generation protected against common chronic illnesses like their older relatives? Why was the younger generation deteriorating so rapidly? Something more than genetics must be involved.
Dr. McDougall’s observation caused him to plunge into the study of the relationship between health and nutrition – a pursuit that changed his practice and life forever. It wasn’t long before he realized that the observations and conclusions he was drawing from his medical practice were being replicated on a much larger scale by researchers around the world. Scientists were finding that the people who had diets based primarily on plant foods escaped the scourges of degenerative illnesses. In contrast, populations that subsisted on the modern diet, rich in meats, dairy products and processed fare, were ravaged by ailments we now regard as all too common.
Dr. McDougall learned something else, too: given the right diet and lifestyle the body will recover. When we remove the poisons from our lives and replace them with health-promoting food, the body can heal itself, even from illnesses deemed incurable.