Does Your Client Need a Protein Supplement?

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Written by Clean Health Accredited Clinical Dietitian, Astrid Naranjo

You probably get asked this question quite often!. And even though this may not sound attractive, the answer is that it depends on what the context to this question is in terms of your client’s goals and preferences.To understand this better, let’s review the basics first!

Protein is a macronutrient comprised of amino acids, the building blocks of lean body tissue. There is probably no other nutrient that gets as much attention among fitness people that protein does, potentially due to its role in muscle growth and repair. And beyond that, this macronutrient forms a mayor part of the skin, hair, bones, tendons, muscles, enzymes, hormones etc (1).

Protein is found in foods such as red meat, poultry, fish, dairy, eggs, nuts, tofu and legumes but is also available in a variety of formulated supplements drinks, bars and powders.

You probably may have heard that common suggestion from fitness and medical experts that you should be “getting the bulk of our protein from whole, real food sources”. Nonetheless, for some, protein supplements can be helpful as part of their overall diet or dietary strategies, as well as make your client’s life easier especially if they are struggling to meet their protein targets, but they certainly shouldn’t be the main and only go-to source of protein nor they are essential for everyone.

How much protein your client needs typically depends on their exercise/training routine, age and overall health status. Hence, the decision to use a protein supplement could be based on several issues relevant to the individual, including their:
– Training load
– Goals
– Daily energy requirements
– Typical diet
– Appetite post-exercise
– Budget available
– Preferences
– General dietary intake

A good place to start could be calculating your client’s protein requirements to help deciding whether they might benefit from supplementing their diet. The minimum amount thought to be “adequate” for most healthy people (general population/ generally sedentary), called the Recommended Dietary Allowance (RDA), is set at 0.8 grams per kilogram. Nonetheless, protein needs will be higher in the elderly & anyone in a calorie deficit to help support lean body mass which is vital for performance, looks, and metabolic functioning.

There is general consensus that protein needs in active individuals are much higher than in sedentary people. For example for endurance training, protein recommendations are ~ 1.2-1.4 g/kg of body weight, resistance training 1.2-1.7 g/kg of body weight (2). Once protein needs have been calculated, it is time to review your client’s average protein intake.

Are they eating an adequate amount of protein throughout the day, every day?
If they are eating an adequate amount of protein with ease every day, then a protein supplement is probably not essential and further protein intake may not equal more gains (3). Also, protein shakes won’t build muscle better than just consuming other forms of protein through typical food sources, if the actual total protein intake is adequate (3).

If you know that your client isn’t achieving their daily protein requirements, or they struggle to fit it in, then it would be recommended using a protein supplement to get them to their targets, especially on those lower protein days.

Now, when it comes to look at the actual supplements, it is ideal to know whether the type of protein matters as much or not. The nutritional value of a protein is determined by its unique amino acid profile – proteins with a high biological value (HBV) are recommended wherever possible.

Animal based proteins are considered HBV proteins as they contain all of the essential amino acids not able to be created by the human body.
Plant based proteins only contain some of the essential amino acids, hence are considered to be of lower biological value/ incomplete proteins.

Leucine, a branched chain amino-acid, plays a critical role in ‘switching on’ muscle protein synthesis. The leucine content of foods varies but some foods are naturally high in leucine, including milk (and whey protein) and red meat. Research suggests that ~2-3g of leucine maximally stimulates protein synthesis (equivalent to ~20-25g of HBV protein) (4).

The range of protein and amino acid supplements available can be quite confusing. Protein supplements can be broadly classified according to their nutrient profile as either providing protein only (as a single protein source or a protein blend i.e. combination of several proteins). Thus, when comparing different proteins to find what is best for your client, there are several qualities that need to be considered, including amino acid profile, leucine content and digestion rates. Each of these properties will affect the functionality of the proteins and the overall benefit or effect they have.

Whey protein
Whey protein has one of the best quality amino acid profiles and has been shown to stimulate muscle protein synthesis to greater degrees compared to other forms (5) and it is rapidly digested.  Whey is rich in branched chain amino acids (BCAAs), especially leucine, which is been found to be in greater amounts when compared to casein and soy proteins (6).

There are 3 main forms of whey protein:
1. Whey Protein Concentrate (WPC): Typically 70-80% protein by weight with small amounts of lactose (milk sugar) and fat. Cheaper than whey protein isolate,
2. Whey Protein Isolate (WPI): Powder is usually 90% protein by weight, with negligible amounts of carbohydrates (lactose) and fat.
3. Whey Protein Hydrolysate (WPH): Derived from WPC or WPI and characterized by shorter peptides or amino acid chains, supposedly resulting in even more rapid digestion but evidence to date is conflicting.

A HBV protein similar to whey and found in milk. Casein clots in the acidic environment of the stomach, resulting in slower digestion and delivery of amino acids to the body. While previous research shows casein does not stimulate muscle protein synthesis to the same degree as whey, casein has been shown to inhibit whole body protein breakdown (7). Hence, this is why casein protein can be a great choice before bed, when there is a longer period without food. There has been research to suggest that having ~ 40g of casein protein before bed can elicit muscle protein synthesis rates effectively and improve whole-body protein balance during post-exercise overnight recovery (8).

Egg Protein (albumin)
A high quality protein source with adequate levels of leucine and other essential amino acids, free of fat and carbohydrate. It is more expensive than whey and casein protein. However, it is a great alternative for those who may have milk allergies or who are unable to properly digest whey or casein.Research is lacking when it comes to directly comparing the effects of whey and egg protein; however, egg protein is a viable source to increase muscle protein synthesis for those who are looking for an alternative to whey.

Soy Protein
Soy protein is the only plant-based protein considered to be a HBV, rapidly digested protein. Available as both a soy concentrate and soy isolate. It is often used in mixed protein supplements and protein bars. Soy protein has less leucine compared to whey which, as discussed, is the key amino acid to signal our body to lay down new muscle tissue and may not be an optimal protein source post workout to maximize muscle growth (9). However, it can still be beneficial if your client can’t consume whey or other high-quality sources (i.e. if you are lactose intolerant or vegan).

Hemp Protein
Hemp protein is derived from the seeds of the cannabis plant that’s gained popularity in recent years. It is considered to be a vegan, easy-to-digest and HBV, hypoallergenic protein but often one of the most expensive protein powder available. Regarding its quality, more research seems to be needed.   Because of the really earthy flavour of hemp protein, it’s probably best as a thickener to a smoothie rather than being the main component/flavour.

Pea Protein
Thought you’ve seen them all? Pea protein is a considered a complete protein made by isolating the protein from ground yellow peas, forming a beige powder. It is a great source of iron, containing around 5–7.5 mg of iron per serving. It still remains deficient in certain amino acids and should not be used as a primary source of dietary protein. Naturally vegan, gluten-free, dairy-free and does not contain any of the top eight food allergens — peanuts, tree nuts, eggs, fish, shellfish, cow’s milk, wheat and soy, though it can be tough on the taste buds (10).

Takeaway: All of these protein supplements, and others that aren’t listed, can be used to get extra protein into your client’s diet, especially if they are struggling to meet their protein targets. If their diet is quite balanced and they are having a protein source in each meal, there wouldn’t be a need to stress too much about what’s best but what is more affordable, enjoyable and can help  them occasionally when they are low in protein or those days they need more convenient food options at hand!

Want to learn the science behind the macronutrients, so an in-depth look at your proteins, carbs, fats, water & how they affect the body depending on the client, goal & a variety of other factors? Enrol into the Performance Nutrition Coach Certification Bundle (includes Level 1 & 2!).


(1)    Dietary protein – its role in satiety, energetics, weight loss and health. Westerterp-Plantenga MS, Lemmens SG, Westerterp KR. Human Biology, Nutrim, MUMC, Maastricht University, Maastricht, Netherlands. British Journal of Nutrition. 2012 Aug;108 Suppl 2:S105-12.
(2)    Rodriguez NR, Di Marco NM, Langley S. American College of Sports Medicine position stand. Nutrition and athletic performance. Med Sci Sports Exerc. 2009; 41:709-731.
(3)    Morton RW, Murphy KT, McKellar SR, et alA systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine 2018;52:376-384.
(4)    Daniel J. Wilkinson, et al. Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women, Clinical Nutrition, Volume 37, Issue 6, Part A, 2018.
(5)    Tang, J. E., Moore, D. R., Kujbida, G. W., Tarnopolsky, M. A., & Phillips, S. M. (2009). Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. Journal of applied physiology, 107(3), 987-992.
(6)    Norton, L. E., Wilson, G. J., Layman, D. K., Moulton, C. J., & Garlick, P. J. (2012). Leucine content of dietary proteins is a determinant of postprandial skeletal muscle protein synthesis in adult rats. Nutrition & metabolism, 9(1), 67.
(7)    Boirie, Y., Dangin, M., Gachon, P., Vasson, M. P., Maubois, J. L., & Beaufrère, B. (1997). Slow and fast dietary proteins differently modulate postprandial protein accretion. Proceedings of the National Academy of Sciences, 94(26), 14930-14935.
(8)    Groen, B., Pennings, B. A. R. T., Beelen, M., Wallis, G. A., Gijsen, A. P., Senden, J. M., & Van Loon, L. J. (2012). Protein ingestion before sleep improves postexercise overnight recovery. Medicine and science in sports and exercise, 44 (8), 1560-1569.
(9)    Phillips, S. M., Tang, J. E., & Moore, D. R. (2009). The role of milk-and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. Journal of the American College of Nutrition, 28(4), 343-354.
(10) Ho MH, Wong WH, Chang C. Clinical spectrum of food allergies: a comprehensive review. Clin Rev Allergy Immunol. 2014;46(3):225-240. doi:10.1007/s12016-012-8339-6

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