10 things to know about meat protein

Image source: www.honestweight.coop modified by WS

Unravelling the controversy

The amount of protein in different (generally 100g) portions of food. Source: https://www.bbc.com/food

Debate has been raging for weeks now about whether we should be eating meat, whether it is good for us, or whether becoming vegan might be better for the planet.  There is a lot of rather biased, hysterical and misleading information going the rounds.  This article will, I hope, help to give you the information you require to make your own decision.

1. The need

We all need protein and the amino acids that they are composed of to sustain life.  Protein, along with carbohydrates and fats are the three essential major nutrients (macronutrients).  Unlike carbohydrates and fats, our bodies are not adept at storing reserves of protein.  That means that if you ever go short on protein, the body will breakdown skeletal muscle in order to keep vital organs and body processes going.  We need protein to build strength, make and renew cells, strengthen immunity and fight diseases like cancer.

2. Animal or vegetable?

At a bio-chemical level protein, whether it is derived from an animal or vegetable source, is the same. During digestion all protein is broken down into its constituent amino acids and the products re-built into new strings of chemicals that may become DNA, or help build bones, or might become a hormone like insulin. Proteins even contribute to mood enhancement by supplying sertonin to the brain.  The thing that all body builders know is that protein is essential for building muscle.  But while they are focused on building pecs, ‘ceps and quads the really crucial protein goes first into building and maintaining our organs.  The heart is a muscle and composed of proteins just like a six-pack.

Animal and vegetable proteins can be equally beneficial, though are not always equally digestible, or available in the correct mix to be equally useful.  Eggs and milk have been found to contain one of the most beneficial and easily digestible mixes of amino acids and they are scored depending on their content.  Here are some typical values:

Protein Digestibility–Corrected Amino Acid Score. (Schaafsma, 2000)

Proteins with higher than 100% values can be used in combination with lower protein value foods.  A classic example of this is the combination of milk and bread. The high lysine content of milk can compensate for the lower concentration in the wheat. Vegetarians can take advantage of this is formulating a healthy diet. (See the infographic at the head of this article)

3. How much do we need?

The world health organisation has been gathering research on protein consumption since WWII.  Their advice is that we need about 0.8g pure protein for every kg of weight per day. Public Health England say 0.75g/kg weight/day. It is best to eat protein at every meal. If you are still growing muscle and bone (under 25), sick, or over 50, many countries now suggest that eating nearer 1g/kg/day may be beneficial.   Some nations, like Norway and Australia/NZ recommend that protein be considered as a percentage of the diet, ranging from 10-20%. That boils down to an average protein requirement for a man or woman of normal weight of three good meals a day, each containing 15-20g pure protein.

If you eat meat, this quantity is pretty easy to achieve.  In fact, in countries like the USA, protein consumption is often far higher than this.  However, it is far more difficult to achieve this level solely from vegetable foods.  For example, 100g lean braising beef contains more than three times the quantity of protein compared to the same weight of cooked lentils (20g:6g).  Vegetables like broccoli, mushrooms or avocado, though they contribute a little protein, should not be considered a main meal source. Half an avocado contains only 2g of protein.

4. Welfare protein

Some people have an ethical objection to eating living things.  But to say that red meat should be left uneaten, may be step too far for you.  If you do decide to eat red meat remember that it isn’t the best source of protein, but it is a good source. However, meat is a very good source of heme iron, which is easily absorbed.  Eggs, chicken, fish and pulses also contain good quantities of readily available iron. Eating vegetable iron with vitamin C can improve the uptake of this non-heme iron, but we’re still not sure to what extent.

Anyone contemplating giving up all animal products, altogether, should seriously consider the danger of a compromised nutrition. A vegan diet can not only reduce the protein we eat, but reduce our stocks of Iodine, Vitamin B12, Calcium, Iron and Vitamin D.   It isn’t by any means impossible, but it does require very careful menu planning, or a shedload of artificial supplements.  Be very careful with the young, the elderly, the pregnant or the sick, who are less resilient to malnutrition. Even the vegan society recommends that vegans take a B12 supplement.  The worry about all these nutritients is that deficiency may not show up until years later, after it is too late.

5. Processed protein

There is now little doubt that processed protein of any kind is bad for us. Recent studies have linked processed meat to cancer and cardiovascular disease.  I would advise a very moderate intake of processed meats like sausages, bacon and jerky.  These contain nitrates and nitrites (bio-active salts) that can interfere with our metabolism. Processed meats have a higher fat and sugar content than unprocessed meat and leaner proteins such as eggs, milk, soy of fish.  Careful scrutiny of the nutrition label is essential for processed foods of all kinds and processed meat products in particular – even those bearing an organic label.

Just because a product is marked as vegan, or organic does not mean it hasn’t been subject to factory processes that have denatured the proteins, added harmful chemicals and reduced the level of nutrition.  For example, many milk substitutes are no nutritional match for whole cow’s milk.  The substitutes lack essential nutrients and most are packed with added sugars, saturated fats and chemicals. Almost all so-called milk substitutes are liberally dosed with artificial supplements such as calcium carbonate, which is chalk.   So if you decide to go down that route be aware that you aren’t eating a natural product but a processed product and all the caveats above still apply.

6. Lean protein

The high fat content in beef and pork make them less beneficial than pulses, soy, milk or fish. If you want to lose weight, restrict yourself to lean proteins, by which I mean chicken, fish, whole milk, soy and legumes.  The protein in cheese, nuts and meat is high quality, but can add weight.  On the other hand, the fats in milk, while being flavoursome and plentiful, seem to react well in our digestion and not to cause the cardiac harm that other saturated fats are known for.  In fact, several recent epidemiological studies show evidence that consumption of full fat milk and yoghurts significantly reduces the risk of cardiovascular and heart disease (1).

7. Organic Protein

Protein is a very active substance.  It is composed of long strings of hydrogen, nitrogen, carbon and oxygen molecules folded and twisted into complex forms. They are held together by electro-chemical bonds which may be strong, such as the peptide bond that links a carbon atom to nitrogen. Bonds may be caused by the strong attractions of minerals, between elements like selenium, manganese, zinc or iron.  Alternatively, the bonds may be electrostatic like the forces that cause hydrogen atoms to shoot about within protein structures, or be powered by the weak and transient Van der Waals forces between atoms.  The upshot of all this complexity is that under the scrutiny of an electron microscope proteins seem to dance and sway.  They form portals, opening and closing to let substances into and out the cells; they form complex runs, like rails, along which other proteins progress like trains; they form claws that can capture and engulf viruses. Miraculously, within every cell in the body, proteins form and re-form again and again to make the perfectly beautiful double helix structure of DNA, creating a blueprint for cell division, regrowth and, of course, reproduction.

We get nutrients like zinc ans selenium from the ground.  Grass fed animals are healthier themselves, and they pass on these important nutrients in their meat and milk.  Zinc deficiency is rising in western society.  Lack of zinc is furst observed in hair loss and an inability to shake-off infection.

8. Pollutants

Hormones, pesticides and fertilizers, which are designed to interfere with microbes, weeds and pests can also interfere with many bodily functions at the bio-chemical level.  So organic produce, where such contamination has been reduced to the bare minimum, makes perfect sense to me.  When you eat a highly dosed foodstuff you may be unwittingly ingesting highly active chemicals and additives than come along for the ride.  Pesticides are so chemically similar to nerve gas that they are stringently controlled in most western countries – but residues exist in everything we eat.

If you live in a polluted city, where you are breathing in other bio-active chemicals, then eating organic may be even more important.  However there is, as yet, no difinitive study that shows that organic is better than non-organic.

9. Contamination

Within proteins any contaminants can get a free ride, causing havoc.  Because we are genetically so similar to other mammals there are dangers of ingesting artificial hormones from mammalian meat, as well as contracting diseases that can jump species like BSE.  BSE in the UK was found to be caused by giving cows feed contaminated by blood and bone from waste meat.  However, in general, strict food regulations in the European Union limit contamination quite sucessfully. Just check where your food is actually coming from.

9. Sustainable protein – eating grass fed.

Some meat production causes high levels of greenhouse gas emissions.  In particular ruminants emit large quantities of methane, which is a greenhouse gas, hundreds of times more potent than CO2.   If the animal is fed on cereal, grown with artificial fertilizers then the emissions can be thirty times higher than the emissions from producing the same weight of vegetables or fruits (Rose, 2019). That is why we are all being advised to eat less meat.  But no reputable scientific evidence suggests that there is an immediate imperative for us to give up meat eating all together, or to give up dairy and poultry.

A sustainable diet is one that uses the least resources to deliver the most nutrition, in perpetuity.  And while some systems can produce high yields in the short term, it is organic and natural farming that maintains good soil composition and can thus secure high yields and maximum nutrition in the long term.  Land which cannot be used for arable crops lends itself to highly efficient livestock farming.  Some studies have shown that this type of meat rearing can be highly efficient and actually contribute to reducing greenhouse emissions.

Artificially fed animals, and I include farmed salmon and shed-reared chickens in this category, do not contain the same nutrients as their more natural grass-fed counterparts.  We are all what we eat. If we sat around all day eating low-grade cereals, we would become sluggish and fat too!  In fact, wild salmon is almost a different species to the farmed variety and has a far superior nutritional profile.

In the infographic below, the co2 emissions of eggs are less than rice, chickens (not shown on the diagram below) less than ruminants and fish from the sea don’t figure at all!

Source: Baker,(2018)

Imported food, will inevitably have clocked up a large number of air miles, using energy to deliver it.  Out of season products grown in a greenhouse may have required artificial lighting, heating and watering, all increasing the energy used to produce them and thus decreasing their sustainability.  In this situation GYO or buying in-season, direct from the farmer is the best of all possible worlds.  A small amount of grass-fed meat, delivered freshly and from a local source may actually be helping the environment, by sequestering CO2 back into the soil.  Similarly a highly processed meat-free alternative might be inferior nutritionally, and might have cost an environmental arm and a leg to make, package and deliver.

10. So what?

In deciding where you will draw your own lines, I would advise thinking about three things.

  • Don’t stint on protein. First and foremost consider your own health and the needs of your family. That means, among other things that you should check that you are all eating enough protein.  Take immediate steps to rectify things if you aren’t.
  • Go for quality. Ensure that your diet contains produce that is safe for you and for the environment. I’d advice seeking the most local, freshest and least processed food you can afford.
  • Look at the whole picture. Consider the entire production process in the food you buy and where you shop.

It is no good berating a friend for eating meat one day a week, if they walk to a local butcher, buy grass fed organic and use every scrap, while you take the Ranger Rover to buy an intensively farmed, imported, factory produced, meat substitutes.  Have a little understanding for your fellows along the way.  The debate has become quite nasty, and that’s not good for any of us.

Further reading:

Look at food labels.  They tell you a lot about what you are buying.

Baker, Katherine, (2018) Counting Calories? Count Your Carbon, Too ENVIRONMENTAL HEALTH, FOOD POLICY AND OBESITY Columbia Mailman School of Public Health  Jun. 2018 https://www.mailman.columbia.edu/public-health-now/news/counting-calories-count-your-carbon-too

Go Grass-Fed! The Benefits of Buying Pasture-Raised Meats from Honest Weight


Links to the science:

British Nutrition Foundation (2016) Nutritional Requirements website. https://www.nutrition.org.uk/attachments/article/234/Nutrition%20Requirements_Revised%20Oct%202016.pdf  Note that BDA recommend a slightly lower level of Protein than other international sources.

Cook and Reddy, (2001). Effect of ascorbic acid intake on nonheme-iron absorption from a complete diet. American Journal of Clinical Nutrition 2001;73:93–8. https://academic.oup.com/ajcn/article/73/1/93/4729737

  1. Dehghan, Mente, Rangarajan et al., (2018) Association of dairy intake with cardiovascular disease and mortality in 21 countries from five continents (PURE): a prospective cohort study. The Lancet Volume 392, issue 10161, p2288-2297, November 24, 2018

Heller, Willits-Smith, Meyer  et al., (2018) Greenhouse gas emissions and energy use associ-ated with production of individual self-selected U.S. diets. Environmental Research letters Online. 2018;13:044004.


Rose, Heller, & Roberto (2019) Position of the Society for Nutrition Education and Behavior(sic): The Importance of Including Environmental Sustainability in Dietary Guidance. Journal of Nutritional Education and Behavior 2019; 51:3,15.


Schaafsma, (2000) Protein Digestibility–Corrected Amino Acid Score

WHO (2007) Protein and amino acid requirements in human nutrition Report of a joint FAO/WHO/UNU expert consultation (WHO Technical Report Series 935) https://www.who.int/nutrition/publications/nutrientrequirements/WHO_TRS_935/en/