John Yudkin (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 with his recommendation of a low-carbohydrate diet for those wishing to lose weight, and with his warnings that excessive consumption of sugar (sucrose) was dangerous to health.
Early years and education
He was raised in London in a Jewish family that had fled the Russian pogroms of 1905. His father died before his seventh birthday, and his mother had to bring up five sons in considerable poverty. He won a scholarship to Hackney Downs School, and another from there to Chelsea Polytechnic. After gaining his BSc degree in 1929 he briefly considered a career in teaching, but then discovered that he could sit an examination for a scholarship to Cambridge. He matriculated at Christ's College, Cambridge as a scholar, and graduated in biochemistry at the age of 20 in 1931.
He worked for his PhD in the Department of Biochemistry at Cambridge under the supervision of Marjory Stephenson, a pioneer of research in bacterial metabolism. His PhD topic was on ‘adaptive enzymes’ (subsequently termed ‘induced enzyme synthesis’). His account of the phenomenon inspired the research of Jacques Monod, who later worked out a detailed mechanism for the induction of enzymes in bacteria and was awarded the Nobel Prize for his work. In 1934, while pursuing his PhD research, Yudkin took up medical studies and started to teach physiology and biochemistry to medical students, first at Christ’s College and then also at other colleges in Cambridge. He began clinical studies at The London Hospital in 1936, while continuing to teach in Cambridge one weekday and at weekends. In 1938 he completed his medical studies, and was appointed Director of Medical Studies at Christ’s College. The same year, he started research at the Dunn Nutritional Laboratory in Cambridge, working principally on the effects of dietary vitamins. 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. However, the studies also showed serendipitously that children from a poorer area of Cambridge were shorter and lighter, and had lower haemoglobin levels and a weaker grip, than those from a wealthier area. Moreover, children from three industrial towns in Scotland were, on average, inferior in the same four measurements to the average Cambridge child, and the children from the poorer families in the Scottish towns were inferior in these measurements to those from the wealthier families. These findings probably helped to persuade Yudkin that nutrition was not only a biological science but also had important social and economic components and implications. In 1942 he wrote an article in ‘’The Times’’ (published anonymously, as was customary in those days) pointing out that there were a large number of organisations in the UK concerned in some way with nutrition – the Ministry of Food, the Ministry of Health, the Medical Research Council, the Cabinet Advisory Board on Food Policy, etc. – but no single body responsible for formulating a uniform plan for nutrition; what was needed was a UK Nutrition Council with oversight of food policy. The suggestion fell on deaf ears.
During the Second World War he served in the Royal Army Medical Corps and was posted to Sierra Leone. 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. 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). This diet was, on paper, adequate in all nutrients – including riboflavin, which was supplied predominantly from millet. But it turned out that millet, although a staple in the Gold Coast and Nigeria, was loathed by soldiers from Sierra Leone, who would not eat it even if they were hungry. This experience must have brought home to Yudkin the importance of custom and upbringing in determining man’s choice of foods.
In 1945, shortly after the end of the war, he was elected to the Chair of Physiology at King’s College of Household and Social Science in London (which became Queen Elizabeth College in 1953). Over the next several years he persuaded the College and the University of London to establish a BSc degree in Nutrition (the first degree in Nutrition in any European university). Students for the degree 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 first students were admitted in 1953, and in 1954 the Department of Nutrition was officially opened and Yudkin’s Chair was converted into a Professorship of Nutrition. During the following years the Department won an international reputation not only for the strength of its research in the physiological and biochemical aspects of the subject, but also for work in such topics as nutrition in the elderly, food surveys in defined populations and the psychology of food choice, and it attracted numerous students from outside the UK, many of them from developing countries.
Yudkin’s publications from the Department showed an unusual breadth of interests, including (in addition to biochemistry) further studies of adaptive enzymes, nutrition and public health, diseases of affluence, food choice both in human beings  and in experimental animals, and historical aspects of the human diet. But his concern became increasingly focused on two topics: the treatment of overweight and the harmful effects of excessive sugar (sucrose) consumption.
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 showed that in most patients weight could be well controlled by restricting dietary carbohydrate. ‘’This Slimming Business’’ (1958), which expressed this idea in user-friendly language, proved popular: it was republished in paperback in 1962, reached its fourth edition in 1974, reappeared as ‘’Lose Weight, Feel Great’’ in the USA, was translated into Dutch and Hungarian, and spawned ‘’The Slimmer’s Cook Book’’ in 1961 and ‘’The Complete Slimmer’’ in 1964.
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. This increase was of great concern to health professionals, and it was widely attributed to an increase in the amount of fat, or of a particular type of fat, in the diet. In a paper published in 1957 Yudkin analysed diets and coronary mortality in different countries for the year 1952, and also analysed trends in diet, and trends in coronary mortality, in the UK between 1928 and 1954. The first of these analyses produced no evidence for the view that total fat, or animal fat, or hydrogenated fat, was the direct cause of coronary thrombosis; in fact the closest relationship between coronary deaths and any single dietary factor was with sugar. The second analysis, that of historical trends in the UK, found no good relationship with any single dietary factor. Instead, it suggested that some change or changes in life style during the past several decades was contributing to the increased incidence of coronary deaths. One obvious change was reduced exercise, and another was alterations in diet.
One implication of the finding that carbohydrate restriction in obese patients causes them to lose weight is that excessive carbohydrate consumption is likely to be a cause of obesity in the first place. An obvious possible culprit is sugar, which provides calories but no nutrients whatever. Given the dramatic increase in sugar consumption during the first half of the century, Yudkin started to suspect that excessive sugar in the diet might contribute not only to obesity but also to coronary heart disease. Studying historical data from many different countries, he found that increasing prosperity leads to an increase in sugar consumption, particularly in manufactured foods, and also that the ready availability of sugar-containing manufactured foods even in the poorer countries may lead to their being bought in preference to more nutritious food. 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]’. Investigating whether any link between sugar consumption and disease could be shown in individual patients, he and his associates in the Department of Nutrition found that patients with atherosclerotic disease (a frequent precursor of coronary heart disease) consumed significantly more sucrose than control patients. An obstacle to the acceptance of these ideas was the belief at the time that sugar and starch were metabolised in the same way, so that one would expect no difference in their effects. Yudkin and his associates, however, fed both experimental animals and human volunteers with differing quantities of sugar and starch, and found major differences between the two carbohydrates in their metabolic effects. 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.
‘’Pure, White and Deadly’’
Yudkin’s ‘’Pure, White and Deadly’’, published in 1972, was written for a lay readership. Its intention was to summarize the evidence that the over-consumption of sugar was leading to a greatly increased incidence of coronary thrombosis, and that in addition it was certainly involved in dental caries, probably involved in obesity, diabetes and liver disease, and possibly involved in gout, dyspepsia and some cancers. The book drew on many studies from Yudkin’s own Department and also on much other biochemical and epidemiological research in the UK and elsewhere. ‘’Pure, White and Deadly’’ was extremely successful. It appeared as ‘’Sweet and Dangerous’’ in the USA, and was translated into Finnish, German, Hungarian, Italian, Japanese and Swedish. A revised and expanded edition was published in 1986. The last paragraph of Chapter 1 begins ‘I hope that when you have read this book I shall have convinced you that sugar is really dangerous.’ The message was naturally extremely unwelcome to the sugar industry and to the manufacturers of processed foods who used (and use) sugar in large quantities in their products, and these firms employed a number of methods to impede Yudkin’s work. The final Chapter of ‘’Pure, White and Deadly’’ lists several examples of attempts to interfere with the funding of his research and to prevent its publication. It also gives examples of the rancorous language and personal smears that the American epidemiologist Ancel Keys, who had proposed that saturated fat was the primary cause of heart disease, employed to dismiss the evidence that sugar was the true culprit. 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.
In 2009 Dr Robert Lustig, a paediatric endocrinologist of the University of California, San Francisco, Medical School who has a special interest in childhood obesity, made a video called Sugar: The Bitter Truth (accessible on YouTube) Dr Lustig and his colleagues had discovered, independently of Yudkin’s work, that sugar has serious deleterious effects, particularly in the aetiology of diabetes and obesity. In his video Dr Lustig referred to his re-discovery of and admiration for Yudkin’s research. The enormous popularity of the video (which has been viewed several million times) has contributed to a great resurgence of interest in Yudkin’s work. ‘’Pure, White and Deadly’’ was republished in 2012 (40 years after its first appearance), with an Introduction by Robert Lustig, and this 2012 edition has been translated into German and Korean. Articles on Yudkin’s work, and on the way in which the food industry denigrated and obstructed his research, have appeared in the lay press  and in television programmes in the UK, Australia and Canada.
Marriage and Family
He married in 1933 Milly Himmelweit, who had recently left Berlin to escape the worsening political situation, and the marriage lasted until her death in March 1995. They had three sons, Michael (born 1938), Jonathan (born 1944, died 2012) and Jeremy (born 1948).
He retired from his Professorship in 1971 and left the College in 1974. He continued to write research papers and books. ‘’This Nutrition Business’’ appeared in 1976 (and was later translated into Spanish), ‘’A-Z of Slimming’’ in 1977, ‘’Eat Well, Slim Well’’ in 1982, ‘’The Penguin Encyclopedia of Nutrition’’ in 1985 (later translated into French), and ‘’The Sensible Person’s Guide to Weight Control’’ in 1990. He also continued to write popular articles in lay magazines, having by now become a household name. 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. He also began to collect antiquarian books, specialising in medicine, nutrition and the culinary arts; after his death much of his collection was given to the National Library of Israel, Jerusalem. He died in London on 12 July 1995.
Degrees and Fellowships
BSc (London) 1929. BA (Cambridge) 1931. MA (Cambridge) 1934. PhD (Cambridge) 1935. MB, BChir (Cambridge) 1938. FRSC (1938). MD (Cambridge) 1943. MRCP (1946). FIBiol (1958). FRCP (1975). Fellow of King’s College, London (1971). Honorary Fellow of the Hebrew University, Jerusalem (1993).
Books written by John Yudkin alone
- This slimming business (MacGibbon and Kee, London, 1958)
- The complete slimmer (MacGibbon and Kee, London, 1964)
- Pure, white and deadly: the problem of sugar (Davis-Poynter, London, 1972)
- This nutrition business (Teach Yourself Books, Sevenoaks, 1976)
- A-Z of slimming (Davis-Poynter, London, 1977)
- Eat well, slim well (Collins and Davis-Poynter, London, 1982)
- The Penguin encyclopedia of nutrition (Viking, Harmondsworth, 1985)
- The sensible person’s guide to weight control (Smith-Gordon, London, 1990)
Books written or edited by John Yudkin and others
- The slimmer's cookbook (MacGibbon and Kee, London, 1961) (co-author with G.M. Chappell)
- Changing food habits (MacGibbon and Kee, London, 1964) (co-editor with J.C. McKenzie)
- Our changing fare: two hundred years of British food habits (MacGibbon and Kee, London, 1966) (editor)
- The Dietary Surveys of Dr Edward Smith 1862-3 (Queen Elizabeth College, London, 1970) (co-author with T.C. Barker and D.J. Oddy)
- Sugar (Butterworths, London, 1971) (co-editor with J. Edelman and L. Hough)
- Fish in Britain (Queen Elizabeth College, London, 1971) (co-editor with T.C. Barker)
- Obesity Symposium (Churchill Livingstone, Edinburgh, 1974) (co-editor with W.L. Burland and P.D. Samuel)
- Diet of man: needs and wants (Applied Science Publishers, London, 1978) (editor)
- "Jacques Monod - Nobel Lecture: From Enzymatic Adaption to Allosteric Transitions". Nobelprize.org. Nobel Media AB 2013. <http://www.nobelprize.org/nobel_prizes/medicine/laureates/1965/monod-lecture.html>
- Yudkin, John (1944). "Nutritional Status of Cambridge School-Children". British Medical Journal ii: 201–214.
- Yudkin, John (16 and 23 September 1944). "The Nutritional Status of Children and Mothers of Industrial Towns". The Medical Officer.
- Anonymous (28 August 1942). "Food and Food Values". The Times.
- Yudkin, John (October–November 1946). "Riboflavin Deficiency in the West African Soldier". Journal of Tropical Medicine and Hygiene 49: 83–87.
- Yudkin, John (1946). "Some Observations on Nutrition in the West African Soldier". Nutrition, Dietetics, Catering (Spring and Summer): 1–4.
- Mandelstam, Joel; J. Yudkin (1952). "Studies in Biochemical Adaptation. The Effect of Variation in Dietary Protein upon the Hepatic Arginase of the Rat". Biochemical Journal 51: 681–686.
- Mandelstam, Joel; J. Yudkin (1951). "Studies in Biochemical Adaptation. Some Aspects of Galactozymase Production in Yeast in Relation to the 'Mass Action' Theory of Enzyme Adaptation". Biochemical Journal 51: 686–693.
- Yudkin, John (November 1964). "Nutrition Education: For Whom and By Whom?". Home Economics: 16–19.
- Yudkin, John (1961–1962). "Nutrition in the Affluent Society". Memoirs and Proceedings of the Manchester Literary and Philosophical Society 104: 1–12.
- Yudkin, John (1965). "Evolution, History and Nutrition: Their Bearing on Oral Disease and Other Diseases of Civilisation". Dental Practitioner 16: 60–64.
- Yudkin, John (12 May 1956). "Man's Choice of Food". The Lancet: 645–649.
- Yudkin, John (22 June 1963). "Nutrition and Palatability with Special Reference to Obesity, Myocardial Infarction, and Other Diseases of Civilisation". The Lancet: 1335–1338.
- Khairy, Melek; T.B. Morgan and J. Yudkin (1963). "Choice of Diets of Differing Caloric Density by Normal and Hyperphagic Rats". British Journal of Nutrition 17: 557–568.
- T.C. Barker, J.C. McKenzie and John Yudkin (1966). Our Changing Fare. London: MacGibbon and Kee. pp. 150–159.
- Oddy, D.J.; J. Yudkin (1968). "An Evaluation of English Diets of the 1860s". Proceedings of the Nutrition Society 28: 13A.
- Yudkin, John (19 December 1959). "The Causes and Cure of Obesity". The Lancet: 1135–1138.
- Yudkin, John (27 July 1957). "Diet and Coronary Thrombosis". The Lancet: 155–162.
- Yudkin, John (1964). "Patterns and Trends in Carbohydrate Consumption and their Relation to Disease". Proceedings of the Nutrition Society 23: 149–162.
- Yudkin, John; Janet Roddy (4 July 1964). "Levels of Dietary Sucrose in Patients with Occlusive Atherosclerotic Disease". The Lancet: 6–8.
- Al-Nagdy, Sohair; D.S. Miller, R.U. Qureshi and John Yudkin (1966). "Metabolic Differences Between Starch and Sugar". Nature 209: 81–82.
- Akinyanju, P.A.; R.U. Qureshi, A.J. Salter and John Yudkin (1968). "Effect of an "Atherogenic" Diet Containing Starch or Sucrose on the Blood Lipids of Young Men". Nature 218: 975–977.
- Yudkin, John (1967). Chemistry, Medicine and Nutrition: Symposium held in Bristol on 14-15 April, 1966. London: Royal Institute of Chemistry. pp. 33–44.
- Lustig, Robert H. (July 2009). Sugar: The Bitter Truth. UCTV.
- Taubes, Gary. (April 13, 2011) Is Sugar Toxic?. The New York Times. http://www.nytimes.com/2011/04/17/magazine/mag-17Sugar-t.html?pagewanted=all&_r=0
- Rumbelow, Helen (9 January 2014). "Sugar: The Bitter Truth". The Times. http://www.thetimes.co.uk/tto/life/food/article3969406.ece
- Llewellyn Smith, Julia (17 February 2014). "John Yudkin: The Man Who Tried to Warn Us About sugar". Daily Telegraph. http://www.telegraph.co.uk/health/dietandfitness/10634081/John-Yudkin-the-man-who-tried-to-warn-us-about-sugar.html
- Pursglove, Anna (3 March 2014). "Special report: Sugar - the bitter truth?". Mail Online. http://www.dailymail.co.uk/home/you/article-2568682/Special-report-Sugar-bitter-truth.html
- Sugar and the heart: old ideas revisited(subscription required)