That food can cure illness isn’t exactly a new idea.

More than 2,000 years ago, the Greek physician Hippocrates, considered the Father of Medicine, famously wrote, “Let food be thy medicine.”

I’ve just been reading Curing the Incurable (Hammersmith, 2020) by Dr Jerry Thompson, a noted member of the British Society of Ecological Medicine. Thompson offers enormous scientific evidence that plant compounds in certain foods are potent cancer killers capable of inhibiting cancer cell growth or causing cancer cell death, blocking metastasis, protecting DNA, increasing natural killer cells and much more.

But the most interesting aspect of his book concerns the role of bad nutrition on communities. Northern Irish physician Dr Robert McCarrison, one of the first researchers to carry out experiments demonstrating the effect of nutrition on the epidemiology of disease, lived in India for years.

There he witnessed extraordinary differences in health between certain portions of the population. Those in the north of the country enjoyed rude good health, whereas many in the south suffered from tuberculosis, heart disease and cancer.

Dr McCarrison decided to test this by first giving rats the diets of the healthiest populations (the Hunzas and Sikhs), which consisted of milk, whole wheat, dahl (lentils), fruits and vegetables, and a little bit of meat. The rats thrived on this diet, developed no detectable diseases, and had a low mortality rate of 1 percent and no infant mortality.

Interestingly, the rats were alert and cheerful, and lived together in perfect harmony. They even allowed the researchers to handle them easily.

Then McCarrison fed another group of rats the typical Southern Indian diet from Madrassi and Bengali (boiled and processed white rice with few fruits or vegetables) or the typical British diet of the time (sugar, tinned food, white bread, boiled vegetables, meat and potatoes).

In short order, their mortality zoomed up to 30 percent, the females experienced more difficult births, and they suffered more stillbirths and miscarriages.

Furthermore, the rats were stunted, had poor coats, and quickly developed diseases like pneumonia and intestinal conditions.

But even more amazing was the effect on their personalities. The rats eating the processed diet were bad-tempered, often bit their human attendants without provocation, and even began killing and eating the weaker rats in their cages.

These results were published in various books of McCarrison’s, but also appear (with photos) on a scientific poster he produced in 1921, now housed in the Wellcome Trust (see https://mccarrison.com/visionaries/mc-carrison/)

As Dr Thompson wrote, “To me it was no surprise that a devitalized diet caused ill health but what did surprise me was how the diet dramatically changed the rats’ personalities and behavior. It is not hard to see similarities with some of the behavior we see in Western societies today and I suspect that if this experiment were repeated today, with the modern British diet, the rats would become even more unpleasant.”

And when epidemiologists have studied those populations with the greatest longevity, they have found several things in common: large amounts of locally grown, fresh organic fruit and vegetables; whole grains; plenty of essential fats; and lots of exercise. Healthy groups eat no sugar or processed food and little meat or dairy, and they avoid excess alcohol, smoking or overeating.

Their robust good health contrasts with that of the populations in Mexico and the Marshall Islands, who suffer some of the highest rates of diabetes, obesity and other aspects of poor health in the world—a situation that occurred right after they traded their traditional diets for one high in junk food and sugary soft drinks.

And in Mexico, at least, one can only speculate whether the widespread adoption of the American junk food diet in Mexico, after 1994, has contributed to a quadrupling of crime since 2007.

Indigenous populations knew what to eat to achieve good health, fertility and healthy offspring—as did the ancient Greeks. But they also knew that holistic foods bred a harmonious and holistic community.

We would do well in the West to recognize that the ultimate cause of our fractured society may have everything to do with the diet we feed ourselves and much of the ‘medicine’ we take to fix the conditions it causes.