The Importance of Protein. Part 2

News Written by Richard Harris

Protein. Good for my muscles AND health, right?


As discussed previously, Protein may just be the most important of the three macronutrients. As well as being good for our muscles, protein is crucial for good health, immunity and for maintaining optimal body composition, and this second part of the ‘importance of protein’ series focuses on the latter.

What is ‘good health’?

Have you ever wondered what defines good health? A lot of people say they’re healthy, but are they?

Health has been defined by the World Health Organization (WHO) as:

“a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.” (1)

Perhaps a truer interpretation of modern lifestyle exists in a recent study in the British Medical Journal (2), whereby the authors suggest health is the ability to adapt to and manage physical, mental and social challenges throughout life.

So. Where does protein fit in amongst all this? Let’s break it down.

Physical Health and Body Composition

According to the above, we need to be able to adapt and manage physical challenges. For those with an active lifestyle, protein and its benefits are obvious and are discussed here in this article. For those who are not as active however can still gain significant health and body composition benefits from higher protein diets.

High protein diets (HPD) are classified as:

“intakes reaching (3) or exceeding (4) 25% total daily energy intake.”

Evidence is now compelling that HPD support weight loss (5). Why is this important? The link between being overweight and chronic illness is apparent (6) and thus the loss of weight, specifically fat, can help reduce the risk of developing such disease. Furthermore, HPD have highlighted several health benefits, both directly and indirectly related to fat loss:

  • Improved blood lipid profiles; reduced triglyceride/LDL cholesterol levels (10), reducing the risk of cardiovascular disease
  • Increased intake of a wealth of vitamins/minerals, enhancing one’s lymphatic and immune system responses (11, 14)
  • Improved sleep quality and wound healing abilities (12)
  • Improved control of blood sugar levels, reducing cardiometabolic risk factors (diabetes) (7)

Furthermore, when thinking of body composition and fat loss, it is suggested that HPD allow those on a hypocalorie (calorie deficit) or even isocaloric diet (maintenance) to maintain said dietary lifestyles in the longer term, due to protein’s satiety factor (7, 10). One of the biggest challenges with weight loss is maintaining the weight lost, hence the importance of adhering to a HPD.

Satiety Factor and Thermogenesis

Of the three macronutrients, protein has the highest satiety factor of all, keeping us full for longer (13). If one is on a weight loss, hypocalorie diet (eating less than their total daily requirement), feeling full will reduce our temptation to reach for that tin of biscuits or sweets, due to a reduction in hunger from feeling full more consistently (10). Furthermore, research highlights that subsequent reductions in total daily energy intake occurs, reducing how much we eat as a result of higher satiety (10, 15). The net result of all this = a sustainable calorie deficit = fat loss.

Protein is also said to be the most ‘expensive’ macronutrient metabolically; it has the highest thermogenesis, or ‘thermic effect of food’ (15). Evidence suggests this will maintain or even increase our total daily energy expenditure (metabolism) (17), when compared to eating a diet composed more of carbohydrates and fats. This is a vital point when trying to improve body composition, as we want to maintain as much of our fat free mass (FFM; muscle) as possible. Fortunately for us, evidence is now clear that HPD favour the retention of FFM (16), even when on a hypocalorie diet, favouring fat loss and waist circumference reductions (8, 9), improving our overall physical health and body composition.

A vital point

In order to ensure we maintain as much FFM as possible when on a hypocalorie or isocalorie diet, it is vital to consume protein regularly throughout the day, from a minimum of 4 meals. We cover this topic in detail in part 1 of this article series

What about mental and social health challenges?

Mental health is a vast topic, way beyond the scope of this article. However, indirectly, HPD that lead to improved health and body composition (fat loss) will certainly contribute towards improved sense of wellbeing, and thus mental health (10). Furthermore, research has found that consuming protein rich in alpha-lactalbumin (milk proteins) can improve our cognitive performance in times of stress (12).

Socially, we can talk about the availability of protein in modern society. There is no doubt we are a more health conscious nation, meaning food choices are much easier to come by, specifically when choosing a meal or snack. High protein foods are readily available in most situations, meaning maintaining a HPD should be easier than ever before.

Take home message

Just in case the above has bamboozled you, below is a summary of the key points relating to this topic:

  • HPD contribute significantly toward fat loss, improving our overall health
  • HPD improve several health markers, reducing the risk of cardiometabolic diseases
  • HPD can help maintain and even increase our metabolism when in a calorie deficit
  • HPD can improve our sense of wellbeing, as a result of fat loss
  • HPD will improve food choices, displacing highly refined, sugary carbohydrates/fatty snacks due to protein’s satiety factor.
  • To find out how much protein to eat per meal and throughout the day, please see this article here


All that’s left to say now is, aim to eat a HPD!

Yours in health.

Team MPN



  1. Frank, P. (2002). ‘The Preamble of the Constitution of the World Health Organization’,Bulletin of the World Health Organization, 80 (12), p. 982.
  1. Huber, M. et al. (2011) ‘How should we define health?’, British Medical Journal, 26, p.343
  1. Bray, G. et al. (2012) ‘Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating: a randomized controlled trial’, JAMA, 307 (1), pp. 47 – 55
  1. Makris, A. & Foster, G. (2011) ‘Dietary approaches to the treatment of obesity’, The Psychiatric Clinics of North America, 34 (4), pp. 813 – 827
  1. Clifton, P., Condo, D. & Keogh, J. (2014) ‘Long term weight maintenance after advice to consume low carbohydrate, higher protein diets–a systematic review and meta analysis’, Nutrition, Metabolism and Cardiovascular Diseases, 24 (3), pp. 224 – 235
  1. Dong, J. et al. (2013) ‘Effects of high-protein diets on body weight, glycaemic control, blood lipids and blood pressure in type 2 diabetes: meta-analysis of randomised controlled trials’, The British Journal of Nutrition, 10 (5), pp. 781 – 789
  1. Wycherley, T. et al. (2012) ‘Effects of energy restricted, high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials’, The American Journal of Clinical Nutrition, 96 (6), pp. 1281 – 1298
  1. Santesso, N. et al. (2012) ‘Effects of higher-versus lower-protein diets on health outcomes: a systematic review and meta-analysis’, European Journal of Clinical Nutrition, 66 (7), pp. 780 – 788
  1. Halton, T.L. & Hu, F.B. (2004) ‘The Effects of High Protein Diets on Thermogenesis, Satiety and Weight Loss: A Critical Review’, Journal of the American College of Nutrition, 23 (5), pp. 373 – 385
  1. Staples, A.W. et al. (2011) ‘Carbohydrate does not augment exercise-induced protein accretion versus protein alone’. Medicine and Science in Sports and Exercise. 43, pp. 1154 – 1161
  1. Markus, C.R., Olivier, B. & De Haan, E.H. (2002) ‘Whey protein rich in alpha-lactalbumin increases the ratio of plasma tryptophan to the sum of the other large neutral amino acids and improves cognitive performance in stress-vulnerable subjects’, American Journal of Clinical Nutrition, 75 (6), pp. 1051 – 1056
  1. Pesta D, Samuel V. (2014) ‘A high-protein diet for reducing body fat: mechanisms and possible caveats’, Nutrition and Metabolism (London), 11 (1), p. 53
  1. Hasler, C.M. (2000) ‘The changing face of functional foods’, Journal of the American College of Nutrition, 19 (Suppl 5), pp. 499S – 506S.
  1. Schoenfeld, B.J. & Aragon, A.A. (2018) ‘How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution’, Journal of the International Society of Sports Nutrition, 27 (15), p. 10
  1. La Bounty, P.M. et al. (2011) ‘International Society of Sports Nutrition position stand: meal frequency’, Journal of the International Society of Sports Nutrition, 16 (8)
  1. Leidy H.J. et al. (2015) ‘The role of protein in weight loss and maintenance’, The American Journal of Clinical Nutrition, 101 (6), pp. 1320S – 1329S
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