The protein myth: why high-protein diets are utterly pointless

Nonsensical nutritional claims have been with us for years. Stanley Green, the Protein Man, paraded up and down Oxford Street warning against the dangers of protein for 25 years until his death in 1993, his placards proclaiming gems of protein wisdom such as ‘Less lust, by [sic] less protein.’

Today’s nutribabble comes in the form of high-protein diets. Food manufacturers are offering high-protein versions of everything from Weetabix to Mars bars, along with supplements, powders and snack bars.

Protein makes up the structures of hair, nails, muscle and other tissues, enzymes, hormones and molecules that transport nutrients in the body. When we eat food, the protein is broken down into amino acids in the stomach and then absorbed in the small intestine. The liver sorts out which amino acids the body needs and breaks down those it does not need into urea and ammonia. Excess protein is not stored but excreted by the kidney in urine mainly as urea.

Humans have slow rates of growth and relatively low protein requirements compared to other animals such as pigs. As a rule of thumb roughly 10 per cent of food energy needs to be supplied by protein. On average, protein provides 15 per cent of the energy in the British diet, with 35 per cent of the intake coming from meat, 22 per cent from cereals and 14 per cent from dairy products.

Animal proteins generally provide all the essential amino acids required but the proteins in cereals are deficient in lysine. This is of no consequence if they are consumed with legumes, which are high in lysine. For example, baked beans on toast will meet requirements for the essential amino acids. This explains why even vegans have adequate intakes of protein.

Protein has a growth promoting effect when demands for growth are high. However, once growth has ceased, extra protein does not promote growth. Whey protein is a by-product of cheese-making and has long been known to promote growth in pigs. Hence the association of Melton Mowbray pork pies with stilton production or Parma ham with Parmesan where whey was put in pig swill.

Whey protein is cheap, about $0.9 a pound, but commands a 10-fold greater price when sold as a protein supplement to body builders. The whey protein supplement industry (worth $9.2 billion in 2015) seems to have been telling porky pies. An application for official endorsement of the health claims that whey protein increased muscle mass, muscle strength, endurance capacity, muscle fatigue and repair was trounced by the European Food Safety Authority in 2010. A recent high-quality trial found no effect taking whey protein on top of a normal diet on muscle protein synthesis in older men.

There are many reasons why high-protein diets (more than 20 per cent of energy) are not healthy. They increase the rate of loss of calcium from bones, have adverse effects on pregnancy outcome, are toxic to people with renal or liver disease and are probably best avoided in people with diabetes. Large, long-term observational studies consistently find that people who eat a lot of meat, particularly red meat, sausages and burgers, are more likely to be overweight, develop type-2 diabetes, and die from cardiovascular disease and colon cancer.

The Paleo diet paints a rosy picture of Paleolithic man and advocates a high-protein diet consisting of mainly meat and fish, eggs, nuts, with some fruit and vegetables, but recommends avoiding any processed food including cereals, legumes and dairy products.

However, this diet is based on speculation, as there are no written records. Our knowledge of indigenous hunter-gatherer nomads suggests that their lives were harsh and short. For example, the life expectancy of the Arctic Inuit was only about 28 years. Cereal cultivation and the development of food processing provided food security and allowed the establishment of human settlements, the domestication of animals and caused civilisations to flourish. Indeed, wheat was the key food commodity underpinning Roman civilisation. The labelling of gluten-free products for the benefit of the one per cent of the population with coeliac disease has wrongly encouraged people to think they need to avoid wheat and other cereals.

Increasing protein intake does not increase loss of body fat. While lean meat and fish are quite satiating foods, this is not the case for bacon, sausages, burgers, cheese and salted nuts. Maintaining an adequate intake of protein on a reduced energy intake is important to prevent loss of lean tissue. This is easily achieved by eating everyday foods. For example, porridge with milk for breakfast, a bowl of pea soup with bread, a chicken breast and a small piece of cheese provide enough protein.

Nobody took the Protein Man seriously with his proclamation that protein increased lust. What worries me is that social media and the web have allowed nutribabble to flourish, spreading wrong-headed information, offering false hope and peddling dangerous dietary advice.

Tom Sanders is professor emeritus of nutrition and dietetics at King’s College London


  • So Angry

    Rubbish. The science is clear. If you want to build mass and lose fat it’s protein all the way. As an older male I’ve tried it – and it works.

    • King Kibbutz

      It’s all bollux.

    • Graeme Harrison

      Wow – who needs science when you’ve got anecdote posted anonymously online?

      • Kingofthemountain

        So you don’t work out then or play sport I take it? Protein is key, the shakes allow an easy ~25g of protein but with low calories to help build muscle… protein builds muscle… the article is not ‘Science’ it doesn’t make sense.

      • foljs

        How is a random article more “scientific”?

    • Jon

      I think a key line that I almost overlooked was this:
      “Protein has a growth promoting effect when demands for growth are high.”
      So, if you’re working out, high protein makes sense. Its for the average person burning the average amount of energy that doesn’t really need excessive amounts of protein. Which is what a lot of so-called nutritionists espouse these days.
      The author really isn’t very clear on these points though, which results in a poorly-made argument, IMO.

    • chris66

      Me too! I started weight training and changed my diet at aged 47, I am now 50. Whey and casein powder have contributed in helping change my body composition from borderline obese to where I am now (I was almost 90kg, now 74kg at 5’7″). Protein supplements are a must, especially at as we get older, to ensure we get enough raw protein without consuming other needless calories. Eating good *whole) foods is just as, if not more important, too.

  • quercus33

    Gluten intolerance is rising – about 33 out of 1,000 have some form of gluten intolerance. This is probably due to changes in cereals like GM crops and with it the increased use of glyphosates like Round-up, so it is not only coeliacs that need to seek out gluten-free foods.

    • Oh come on. People self-diagnose and they like to feel special. They’d be far better off choosing better-quality restaurant meals and ready-mades, learning to cook for themselves, and avoiding sugar as a daily additive. The wheat hysteria will pass, as these things do.

      • palustris2

        ‘ready-mades’ = low sugar. lol

    • lolexplosm

      [citation needed]

      GM foods are safe.

      Trace amounts of glyphosate can’t possibly have such a large systemic change in one’s biology.

      • palustris2

        There is so much evidence to the contrary.
        https://gmo-awareness.com/resources/glyphosate/

        • lolexplosm

          Top of page tells me to buy organic and there’s a tomato being injected with a large syringe and a stupid volume of evil looking liquid. Seems legit.

      • quercus33

        You don’t work for Monsanto or Bayer by any chance?

        • lolexplosm

          A logical fallacy. Not that it’s relevant to the discussion but no.

          Do you think they are literally the only companies that make pesticides and GMOs and that scientific consensus is completely wrong? Glyphosate is out of patent, anyone can make it for one.

  • david torres

    Yea low protein diets are better. Only a pencil neck with no gainz would say something stupid like this. Protein builds muscle that is torn when you workout and you need it to rebuild it back. One gram per body weight

    • lolexplosm

      No one needs 1g per body weight, not even professional body builders. It’s a myth partly promoted by the supplement industry.

  • JabbaPapa

    So the high protein diet is necessary, even according to the author, during the growth stage — and BTW this is ordinary high protein one should be talking about here, not industrialised junk marketed to body builders, which we do not feed to our children — and he even grudgingly admits a truth, that it’s a useful element to help stave off muscular degeneration in handicapped or geriatric persons.

    That’s hardly “utterly pointless”.

    Professor Sanders appears to define “protein” rather strangely — most of us think of it as found in things like lean meat, eggs, lentils, chick peas and other such ordinary, simple foods ; not whey, porridge, baked beans on toast, hamburgers, and bacon sarnies.

    The underlying truth here is that not everyone has the same type of metabolism nor digestive functionality, and so there is no one-size-fits-all diet that all should follow. (though a traditional French/Provençal/Catalan Mediterranean diet, if you live there, is the closest I know of to being just that)

    As for the so-called “caveman diet”, it’s not “high protein” except seasonally — it’s based on a hunter-gatherer conception, and whilst of course the hunter part is high protein, the gatherer part does not exclude the vegetable patch, fruits and berries, greens and beans. But one does avoid foods out of season if one follows it, as I understand it, so that it does get a bit high protein in the leaner winter months.

    The extreme example of the Arctic Inuit is utterly ridiculous — it would be like using Eskimos today as an example of ordinary dietary habits in the 21st Century.

    • lolexplosm

      Yes it is silly but the promoters of fad diets like LCHF and paleo use the Inuit and other niche populations as “proof” of their diet’s efficacy.

  • Russ Franey

    I can easily lose weight eating bacon,sausage,hamburgers,and salted nuts. Why in the world would I want to eat porridge and peas?