John Yudkin FRSC (8 August 1910 – 12 July 1995) was a British physiologist and nutritionist, and the founding Professor of the Department of Nutrition at Queen Elizabeth College, London.

He gained an international reputation for his book Pure, White and Deadly (1972), which warned that the consumption of sugar (sucrose, which consists of fructose and glucose) is dangerous to health, an argument he had made since at least 1957.

[6] From the late 2000s, there was a resurgence of interest in his work, following a 2009 YouTube video[7] about sugar and high-fructose corn syrup by the pediatric endocrinologist Robert Lustig, and because of increasing concern about an obesity epidemic and metabolic syndrome.

[1] After gaining his BSc degree in 1929 he briefly considered a career in teaching,[citation needed] but then discovered that he could sit an examination for a scholarship to the University of Cambridge.

His studies of the nutritional status of school children in Cambridge showed that supplementation of the diet with vitamins had little effect on their general health.

While there he studied a skin disease that was prevalent among local African soldiers and discovered that it was due not to an infection, as had been believed, but to riboflavin deficiency.

[16] He found that the Army had devised a uniform diet for its soldiers in the four British West African colonies (Gambia, Sierra Leone, Gold Coast and Nigeria).

[citation needed] Students were taught an integrated series of courses including not only chemistry, physics and biology but also relevant elements of demography, sociology, economics and psychology.

The end of food rationing early in the 1950s brought with it an increase in the number of people who were suffering from obesity, and by 1958 slimming diets had proliferated, many of them with no scientific basis.

Yudkin's interest in sugar arose indirectly from his studies of the alarming increase in many countries during the first half of the twentieth century in the incidence of coronary thrombosis.

[4] In 1964 he wrote 'In the wealthier countries, there is evidence that sugar and sugar-containing foods contribute to several diseases, including obesity, dental caries, diabetes mellitus and myocardial infarction [heart attack]'.

[32] As early as 1967 Yudkin suggested that the excessive consumption of sugar might result in a disturbance in the secretion of insulin, and that this in turn might contribute to atherosclerosis and diabetes.

It also refers to the rancorous language and personal smears that Ancel Keys — the American epidemiologist who had proposed that saturated fat was the primary cause of heart disease — employed to dismiss the evidence that sugar was the true culprit.

Keys wrote, for example: It is clear that Yudkin has no theoretical basis or experimental evidence to support his claim for a major influence of dietary sucrose in the etiology of CHD; his claim that men who have CHD are excessive sugar eaters is nowhere confirmed but is disproved by many studies superior in methodology and/or magnitude to his own; and his "evidence" from population statistics and time trends will not bear up under the most elementary critical examination.

But the propaganda keeps on reverberating ...[34][35]The efforts of the food industry to discredit the case against sugar were largely successful, and by the time of Yudkin's death in 1995 his warnings were, for the most part, no longer being taken seriously.

"[37] In 2009 Robert Lustig, a pediatric endocrinologist of the University of California, San Francisco, with a special interest in childhood obesity, made a video, Sugar: The Bitter Truth.

Articles on Yudkin's work, and the way in which the food industry denigrated and obstructed his research, have appeared in the lay press[9][38][39] and in television programmes in the UK, Australia and Canada.

Having been interested in Israel for many years – soon after its foundation in 1948 he had been asked to advise on the nutritional problems experienced by the new state – he continued in his retirement as an active Governor of the Hebrew University of Jerusalem.