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collage of historical adverts for protein foods

Primed for power: a short cultural history of protein. Section 3: Testing the lower limit: the end of the first protein fashion

3. Testing the lower limit: the end of the first protein fashion

Enthusiasm for protein in the latter half of the 19th century was a bubble — disconnected from the reality of research findings and driven by a series of feedback loops. The concept of protein as a single substance held such theoretical appeal that its influence was felt for decades after it was formally rejected. Research which established dietary requirements by measuring existing dietary habits took place in countries with cultural norms of high meat consumption. Beliefs about meat fitted neatly into ideologies of cultural, racial and national superiority — and the concept of protein established a seeming scientific basis for these beliefs. Scientists engaged in nutritional and agricultural research were often entrepreneurs, and findings that meat was healthsome and necessary offered the marketing tools to capitalise on a newly globalised and technologised meat market. In all of this, exaggerating the physiological importance of protein aligned with the interests of (commercial, social, national and racial) power.

All bubbles must burst in the end, and the seeds of protein doubt had been sown long before the end of the century. Max Rubner, as mentioned above, broke with his mentor Carl Voit and the reigning expert Liebig on protein requirements. He put more weight than they had on the experimental evidence against Liebig’s theory
of nutrition, and concluded that protein, fat and carbohydrate were largely interchangeable sources of dietary energy. By the early 20th century, he had suggested that the protein requirement for a male worker weighing 70kg might be as little as 30g of protein per day99 — less than a quarter the value that he had given at an earlier point in his career, and far lower even than present-day estimates. This did not immediately result in a complete reassessment of the consensus, but it was part of a growing body of evidence complicating the earlier picture of protein. A gradually improving understanding of the chemistry of protein and new methods for exploring dietary requirements also contributed to this.

Since the mid-19th century, the growing vegetarian movement had offered an alternative narrative, both on protein and on meat. Prominent proponents of vegetarianism on religious grounds such as Presbyterian minister Sylvester Graham and later the Seventh Day Adventist J. H. Kellogg argued that consumption of meat led to overstimulation, bodily pollution and spiritual temptation. Kellogg (brother of W.K. Kellogg of breakfast cereal fame)100 explained this as an effect of protein, and the idea that high protein consumption was dangerous developed in the discourse of a number of Christian denominations. In 1914, an advert for shredded wheat biscuits masquerading as an article on prison reform was published in a range of Christian publications in the US, and offers a telling example of the themes at play. The advert suggested that “an excess of high proteid foods” poisoned the blood, disturbed mental equilibrium, caused a “quarrelsome temperament” and might lead to “more heinous crimes”.101,102

Such beliefs had little direct impact on the scientific consensus, with nutritionists rejecting such diets as protein- deficient.103 Proponents of vegetarianism were generally seen as cranks, and parodied variously as enfeebled, effeminate, and living dull lives of indigence. Nevertheless, there was a clear discrepancy between mainstream beliefs about protein and the existence of many people living on vegetarian diets — vegetarian restaurants had multiplied in cities like London and Manchester in the late 19th century — and this prompted researchers like

Voit, Rubner, American biochemist Russel Henry Chittendon and Danish nutritionist Mikkel Hindhede to test whether bodily health could be maintained while eating less meat. Hindhede (whose work was also inspired by a desire to defend the potato-heavy but protein-light diet of his youth in rural Jutland)104 published the results of experiments in which his lab assistant had been obliged to live on only potatoes, butter, and occasional fruit for a year — a diet, in other words, with no meat and no main source of protein. Although monotonous,105 Hindhede claimed that this maintained him in “full vigor”.106 Hindhede found that this work — together with his earlier finding that bovine dietary requirements for protein were much lower than previously thought — was highly controversial in Denmark, leading him to publish a 1913 monograph condemning the work of the German nutritional school and attacking generally accepted views of protein. The book (“somewhat polemical” by its own admission107) concluded that “it would seem to be practically impossible to avoid getting protein enough”108 and indeed that a high protein diet was “probably harmful”. Although he stressed that he was not a vegetarian on principle, he would go on to advocate ovo-lacto vegetarianism as the healthiest diet for the remainder of his career.109

Perhaps the end of the fashion for protein was now an inevitability—or perhaps these arguments could have dragged on in the literature for many more years. However, the First World War created a dramatic break with the past.

The move to war economies in which states held monopsonies on food110 created a need for governments to determine how much protein the agricultural sector should produce; blockades and rationing created a need to determine the minimum diets that could keep populations healthy. This led to greater power in the hands of nutritional scientists and a reification of nutritional science in the context of concrete goals and the opportunity to undertake experiments at enormous scale.

Rubner, heading the Kaiser Wilhelm Institut für Arbeitsphysiologie, was given authority by the German Ministry of War to investigate the role of nutrition in the optimal use of military and industrial labour. Hindhede, head of Denmark’s Statens Laboratorium for Ernæringsundersøgelser, gained even greater authority. Thus two great critics of inflated demands for protein were given unprecedented platforms — but Rubner, who had vacillated on protein requirements over the course of his career, returned to the safe scholarly mainstream of assuming that diets should be high in protein111 and so it was Hindhede’s work that was transformative.

Towards the end of the war, the Danish state was affected by the Allied blockade and faced the challenge of avoiding the same disastrous famine that had already affected Germany. Hindhede centred the idea of feed-food competition112 and recommended that 30-90% of pigs be allowed to starve so that lower quality cereals and vegetables normally used for feed could be repurposed as food. This policy, carried out, actually saw a reduction in human mortality through the period of rationing in Denmark. By contrast, Germany saw a precipitous rise in civilian deaths from starvation and disease — a disparity that completely vindicated both the arguments against high protein requirements and against the specific necessity of meat.113 Hindhede wasted no time in highlighting this in international medical journals.114

Following the War these findings were cemented with new methods of testing specific nutrient requirements in the lab — but Hindhede’s views were becoming mainstream even earlier than this115 and estimates of daily protein requirements dropped precipitously (see Figure 4). Already in 1923, American nutritionist Lafayette Mendel was looking back on the 19th century obsession with protein,116 commenting that long-disproven scientific ideas had left behind a public misconception of “momentous consequence” that “the production of ‘flesh and blood’ requires a liberal consumption of protein, which in turn is commonly interpreted to mean meat”.117 Hindhede, too, was establishing the narrative that the mists of an ideologically-sustained fixation on protein had finally lifted; he described one 19th century nutritionist of the German school as having written “with the manner of a propagandist” in advocating for the importance of protein.118

Nutritional science had broadly reached a consensus that protein requirements were far lower than previously believed and that meat consumption was not a physiological necessity — but this reassessment was tempered by other new research. The identification of individual amino acids had progressed (cf. Figure 3), and the discovery of the distinction between essential and non-essential amino acids through experiments on rats and dogs offered a possible explanation of civilian and military experiences of starvation119 (particularly ‘war dropsy’ or ‘war oedema’, a condition involving swelling that was widespread in Europe — and would be again during the Second World War120). This strengthened a belief in the dietary importance of at least some level of intake of animal proteins, particularly milk.121 What is more, the reassessment of protein and meat never consistently filtered out into other sciences or into public perception. In a 1939 American medical textbook we read that “the prowess and achievements of our early Anglo-Saxon ancestors have been attributed in part to the energy-giving effects of the meat which they consumed in liberal quantities [... and] if man would enjoy sustained vigor and would experience his normal expectancy, as well as contribute to the improvement of his race, he must eat a liberal quantity of good protein”.122 This quote clearly demonstrates the problem: all of the cognitive and cultural biases favouring protein and meat were still there. The power and influence of ‘scientific consensus’ is nothing against the power of a good story.

1917 advert for Bynogen a milk protein, phosphate, and whole wheat/malt extract supplement. The advertisers claim it is "an excellent sustaining and restorative food"

The Scotsman - Monday 07 May 1917



Timeline of discovery of amino acids from asparagine in 1805 to threonine in 1937

Figure 3: Timeline of identification of the amino acids

Figure showing how the recommended daily intake of protein (g/kg/day) has change over time. Overall the trend is a decrease in recommended daily intake from around 2 to 1.5 g/kg/day between 1850 and 1900 to around 0.75 g/kg/day now

Figure 4. Recommendations by institutions and individual researchers for daily protein intake by body weight by year; recommendations mentioned in the text are individually labelled; shaded areas show the two world wars.123


99 Treitel, ‘Max Rubner and the Biopolitics of Rational Nutrition’, 6.

100  Carpenter, Protein and Energy, 79–88. J. H. Kellogg was actually the inventor of corn flakes, which he served at the sanatorium of which he was chief medical officer, but after a feud was forced to give up his rights to the invention to his brother. Kellogg is also credited with inventing peanut butter, and marketing an early meat substitute. Like Liebig and others, his beliefs about nutrition overlapped substantially with his entrepreneurial endeavours.

101  Dan Priel, ‘Law Is What the Judge Had for Breakfast: A Brief History of an Unpalatable Idea’, Buffalo Law Review 68, no. 3 (2020): 928–30.

102  Not all vegetarianism was religiously motivated by any means; for humanist vegetarians, however, the arguments were more about demonstrating the non-necessity of dietary animal protein than its actual harmfulness. Cf. Liam Young, ‘Eating Serial: Beatrice Lindsay, Vegetarianism, and the Tactics of Everyday Life in the Late Nineteenth Century’, Societies 5, no. 1 (22 January 2015): 65–88,

103  John M. Swan, ‘A Study of the Metabolism of a Vegetarian’, The American Journal of the Medical Sciences 129, no. 6 (June 1905): 1059; Carpenter, Protein and Energy, 88–99.

104  Mikkel Hindhede, Protein and Nutrition: An Investigation (London: Ewart, Seymour & Co., Ltd., 1913), 4–5.

105  For earlier researchers, the difficulty of finding test subjects willing to eat such restricted diets for a long period presented a significant barrier to this work—but, experimenting on his lab assistant and himself, Hindhede commented: “I have not encountered these difficulties.” [Diesen Schwierigkeiten bin ich nicht begegnet.]

106  Mikkel Hindhede, ‘Untersuchungen Über Die Verdaulichkeit Der Kartoffeln’, Skandinavisches Archiv Für Physiologie 27, no. 2 (26 April 1912): 277–94; M. Hindhede, ‘THE EFFECT OF FOOD RESTRICTION DURING WAR ON MORTALITY IN COPENHAGEN’, Journal of the American Medical Association 74, no. 6 (7 February 1920): 381, Note that the experiment was not entirely continuous: there were periods in the summer where they could not get potatoes, and Hindhede wrote the work up as a series of slightly different experiments whose total period was over a year. However, in the 1920 paper he summarised it as having shown that ‘man can retain full vigor for a year or longer on a diet of potatoes and fat’, and this rather simplified image of the work has had a long afterlife in popular culture.

107  Hindhede, Protein and Nutrition: An Investigation, 4.

108  Hindhede, 156.

109  cf. M. Hindhede, ‘Ueber den Einfluß der Nahrungsrationierung auf den Gesundheitszustand’, DMW - Deutsche Medizinische Wochenschrift 46, no. 12 (March 1920): 318–20,

110 cf. Simmons, Vital Minimum, 110.

111  Mikuláš Teich, ‘Science and Food during the Great War: Britain and Germany’, in The Science and Culture of Nutrition, 1840-1940, ed. Harmke Kamminga and Andrew Cunningham (BRILL, 1995), 213–34,; Corinna Treitel, ‘Food Science/Food Politics: Max Rubner and “Rational Nutrition” in Fin-de-Siècle Berlin’, in Food and the City in Europe since 1800, ed. P. J. Atkins, Peter Lummel, and Derek J. Oddy (Aldershot, England ; Burlington, VT: Ashgate, 2007), 59; Kristen Ehrenberger, ‘The Politics of the Table: Nutrition and the Telescopic Body in Saxon Germany, 1890-1935’ (Ph.D., Urbana, Illinois, University of Illinois, 2014), 61,

112  Helen Breewood and Tara Garnett, ‘What Is Feed-Food Competition?’, Foodsource: Building Blocks (University of Oxford: Food Climate Research Network, 2020),

113  Hindhede, ‘THE EFFECT OF FOOD RESTRICTION DURING WAR ON MORTALITY IN COPENHAGEN’; Rabinbach, The Human Motor, 262–64; U Heyll, ‘Der „Kampf ums Eiweißminimum”’, DMW - Deutsche Medizinische Wochenschrift 132, no. 51/52 (12 December 2007): 2768–73,; Stephan Rössner, ‘Mikkel Hindhede (1862-1945)’, Obesity Reviews 11, no. 3 (March 2010): 231–32,

114  With the fuller view of hindsight, it is worth noting that historians now agree that Germany’s disastrous experience of starvation in the War was more due to a lack of centralised planning of food and agriculture at all than to policies which privileged meat and protein. Rubner actually advocated similar policies to Hindhede: before the War he had argued that the poor should swap their meat for plant protein sources, and during the War he put a lot of focus on feed-food competition, writing ‘If we had no pigs, we’d have no food worries. Perhaps we’ll learn at least from the war, that swine husbandry is for the politics of food an example of insanity.’ That German nutritional policies were so unsuccessful had much to do with problems of implementation. Nevertheless, the consensus interpretation in the following decades blamed Rubner, “rational nutrition”, and proteincentricity. Heyll, ‘Der „Kampf ums Eiweißminimum”’, 2772; Treitel, ‘Max Rubner and the Biopolitics of Rational Nutrition’, 21–25; Ehrenberger, ‘The Politics of the Table: Nutrition and the Telescopic Body in Saxon Germany, 1890-1935’, 45.

115  Graham Lusk, Food in War Time (Philadelphia and London: W. B. Saunders Company, 1918); Henry C. Sherman, L. H. Gillett, and Emil Osterberg, ‘Protein Requirement of Maintenance in Man and the Nutritive Efficiency of Bread Protein’, Journal of Biological Chemistry 41, no. 1 (1920): 97–109.

116  Lafayette B. Mendel, Nutrition: The Chemistry of Life (New Haven: Yale University Press, 1923), 14–26.

117  Mendel, 24.

118  Hindhede, Die Neue Ernährungslehre, 5, cited in Mendel, 113.

119  although these had equally been associated with excess intake of carbohydrate; cf. John Nott, ‘“No One May Starve in the British Empire”: Kwashiorkor, Protein and the Politics of Nutrition Between Britain and Africa’, Social History of Medicine 34, no. 2 (28 May 2021): 553–76,

120  F.A. Dentz, ‘Hunger Oedema’, Acta Psychiatrica Scandinavica 28 (June 1953): 93–112,

121  Food (War) Committee, Report of the Food (War) Committee of the Royal Society on the Food Requirements of Man and Their Variations According to Age, Sex, Size, and Occupation (London: Harrison and Sons, 1919), 18,; Mendel, Nutrition: The Chemistry of Life, 120–24.

122  James S. McLester, Nutrition and Diet in Health and Disease (Philadelphia: W. B. Saunders, 1939), 77.

123 Halliburton,AText-BookofChemicalPhysiologyandPathology,604,608;MaxRubner,DieGesetzedesEnergieverbrauchsbeider Ernährung (Berlin u. Wien: F. Deuticke, 1902); Swan, ‘A Study of the Metabolism of a Vegetarian’; David McCay, The Protein Element
in Nutrition (London; New York: Edward Arnold; Longmans, Green & Co., 1912), 69, 110; Jules Amar, The Physiology of Industrial Organisation and the Re-Employment of the Disabled, trans. Bernard Miall (London: The Library Press Limited, 1918),; Sherman, Gillett, and Osterberg, ‘Protein Requirement of Maintenance in Man and the Nutritive Efficiency of Bread Protein’; Mixed Committee on the Problem of Nutrition, The Problem of Nutrition, vol. I: Interim Report of the Mixed Committee on the Problem of Nutrition (Geneva: League of Nations Publications Department, 1936); Kenneth L. Blaxter, ‘The Purpose of Protein Production’, in The Biological Efficiency of Protein Production, ed. John Gareth Watkin Jones (Cambridge: Cambridge University Press, 1973), 4; R. Passmore et al., Handbook on Human Nutritional Requirements (Geneva: World Health Organization, 1974), 20; Joint FAO/WHO/UNU Expert Consultation, ‘Energy and Protein Requirements’, World Health Organization Technical Report Series (Geneva: World Health Organization, 1985), 104–5; Subcommittee on the Tenth Edition of the RDAs, Recommended Dietary Allowances (Washington, D.C.: National Academy Press, 1989), 52–66; Cannon, ‘Nutrition’; Jennifer J. Otten, Jennifer Pitzi Hellwig, and Linda D. Meyers, eds., DRI, Dietary Reference Intakes: The Essential Guide to Nutrient Requirements (Washington, D.C: National Academies Press, 2006); Mohammad A Humayun et al., ‘Reevaluation of the Protein Requirement in Young Men with the Indicator Amino Acid Oxidation Technique’, The American Journal of Clinical Nutrition 86, no. 4 (1 October 2007): 995–1002,; WHO, FAO, and UNU, eds., Protein and Amino Acid Requirements in Human Nutrition: Report of a Joint WHO/FAO/UNU Expert Consultation; [Geneva, 9 - 16 April 2002], WHO Technical Report Series 935 (Joint Expert Consultation on Protein and Amino Acid Requirements in Human Nutrition, Geneva: WHO, 2007); Rajavel Elango et al., ‘Evidence That Protein Requirements Have Been Significantly Underestimated’:, Current Opinion in Clinical Nutrition and Metabolic Care 13, no. 1 (January 2010): 52–57, https://doi. org/10.1097/MCO.0b013e328332f9b7; Walter Willett et al., ‘Food in the Anthropocene: The EAT–Lancet Commission on Healthy Diets from Sustainable Food Systems’, The Lancet 393, no. 10170 (February 2019): 447–92,; U.S. Department of Agriculture and U.S. Department of Health and Human Services, Dietary Guidelines for Americans 2020-2025.


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