High-protein diet is the real culprit
From Dr Jerry Thompson
Dr Malcolm Kendrick states that low-fat diets do not help in diabetes and heart disease (Clinical, 7 September). He suggests we would be better with a low-carbohydrate, high-protein diet. Is he right?
Colin Campbell did a series of experiments in the 1960s. He found that animals treated with carcinogens succumbed on a high-protein diet but were nearly immune on a low-protein diet. The experiments were done with a variety of species and with different carcinogens. The results were always the same. It was even possible to switch cancers on and off by altering the amount of protein in the diet. This was true with animal protein but not vegetable protein.
In the most extensive epidemiological study ever conducted – the China Study - there was a clear correlation between animal protein and heart disease, diabetes and cancer, even when levels were much lower than in the West.
International comparisons between countries and studies of groups within countries show the same. Low animal protein, plant-based diets have low rates of diabetes, heart disease and cancer. Migrant studies show that migrants acquire the risks of the country they migrate to and in the case of diabetes this gets greater as the animal protein increases.
Intervention studies show a plant-based low animal protein diet can reverse heart disease (Ornish, Esselstyn, Morrison) and type 2 diabetes (Anderson, Pritiken). Some work also suggests reversal of cancer (Gerson, macrobiotic).
Dietary guidelines were formulated in the US in 1982 but resistance to the idea that animal protein could be a factor in cancer and heart disease was then high. Instead fat was blamed – the American diet was given the all-clear as long as you cut out the fat.
As Campbell points out in his fascinating book on the China study, recent studies such as the Women's Health Initiative have caused confusion by looking at groups with similar animal protein intakes.
In fact in this study fat was negatively correlated with animal protein so it was almost certainly not the high fat but the lower animal protein that proved beneficial in diabetes.