More broadly, we have evolved the digestive system of an omnivore, not a carnivore. And our body chemistry suggests a very long period of substantial fruit intake, not unlike the eating habits of our cousins, the jungle-dwelling primates.

At the moment, some nutritionists are suggesting that a high animal protein/fat diet is healthier. Yet all the meta-analyses indicate that larger intakes of fruit, vegetables and fibre mean substantially less risk for both digestive cancers and cardiovascular disease, while increased meat consumption is clearly linked with an increased risk of developing both conditions.

This is hardly surprising since all meat putrefies and, unlike carnivores, we have a digestive system more geared to larger amounts of fibre. Any unbalanced diet leads to micronutrient deficiencies. However, both meat-oriented and vegetarian-oriented diets can be adapted to provide enough.

However, it is true that grains, our current major source of carbohydrates, were introduced into our diets relatively recently. This is probably why so many people are allergic to them. Yet the number of people sensitive to grains is much lower in cultures such as Egypt, where grains have been grown the longest. In northern countries where grains are not grown but imported, the incidence of gluten sensitivity is very high. It is likely that, in ancient days, those less adapted to eating grains were weaker and hence died off younger, leaving a genetic pool of people who were better adapted.

So, I favour a diet containing fresh fruit, vegetables, seeds, nuts, fish in preference to meat and less grains. This is most consistent with large periods of our ancient history.