Thomas Latimer (Peter) Cleave (1906–1983) was a surgeon captain who researched the negative health effects of consuming refined carbohydrate (notably sugar and white flour) which would not have been available during early human evolution.
[1] Between 1922 and 1927, he attended medical schools at the Bristol Royal Infirmary, and St Mary's Hospital, London, where he was an academic prodigy winning prize after prize and qualifying at the early age of 21, having passed his primary FRCS examination at the age of 18 and ultimately achieving MRCS and LRCP.
At Bristol, one of his teachers was Rendle Short, who had proposed that appendicitis is caused by a lack of cellulose in the diet.
He noticed that the saccharine manifestations did not occur in wild creatures or among primitive people living on traditional unrefined food.
In 1969, Dr. Cleave brought public attention to the low amount of dietary fiber in modern diets that had become rich in processed ingredients.