A Nutritionist's View on Protein Powders

You are spoiled for choice with the variety of protein powders on the market today. As more and more options emerge, from whey to casein to collagen to pea to soy to hemp, perhaps you’ve wondered which protein powder is best for you? Or whether it’s even good for you at all? Do you really need them?


Why you might use protein powders:

1. To help meet daily protein requirements 

Using protein powders can be a useful tool when trying to ensure you are getting enough protein in your diet. One serving of protein powder will normally contain 20-25g of protein and can, therefore, provide a significant contribution to your daily requirements.

But how much do you really need? The answer is not as simple as you would hope.

The RDI (Recommended Dietary Intake) of protein for a healthy adult with a minimal physical activity level is a modest 0.8 g of protein per kilogram (kg) of body weight. For an 80 kg, that would equate to just 64 g of protein per day. Under this model, with just a 20-25g scoop of protein powder you can hit about a third of your daily requirements… excellent!

However, RDI recommendations demonstrate the average daily intake of a nutrient that is sufficient to meet the nutrient requirements of ~98% of all healthy individuals in a particular age and gender group and can, as a result, lack specificity or nuance when applied to individuals. There is now a significant amount of research to suggest that the current RDI for protein may be too low and, as a result, higher protein recommendations are typically recommended for the ‘normal, healthy population’, and even higher for certain other groups.

Therefore, more accurate protein recommendations for active, healthy individuals may then range from 1.4-2.2g per kg of bodyweight (1, 2, 3). The amount, type, duration, and intensity of exercise you do will alter your needs; those that weight train or are trying to build muscle, athletes, or those recovering from injury will require the higher end of the scale. Certain groups such as older adults or pregnant and breast-feeding women may also require specific recommendations. For example, 1-1.3 g per kg of body weight is recommended for those over the age of 65 (4).

The benefits of these higher protein intakes can be seen in weight loss, muscle building, preventing muscle loss, injury prevention and recovery and improved health. Although you don’t need protein powder to reach your daily protein goals - a healthy, balanced and varied diet that includes animal products like meat, fish, eggs, or dairy every day, will likely provide all you need - they can be a useful tool to help you fulfil your personal protein requirements and make sure you are matching your nutrition to your goals on a daily basis.


2. Convenience 

Protein powder can be a convenient, and often cost-effective way, of increasing the protein content of a meal that's typically low in protein, or if you are on-the-go travelling and are not able to have a meal containing an adequate amount of protein. For example, a smoothie made with just fruit and vegetables lacks protein; and even a few tablespoons of nut butter only adds about 4-7 g. Blending in a protein powder can easily increase the protein content to a more significant percentage of your daily needs. 

Protein powders are also incredibly versatile; as well as blending well into smoothies, you can add it to porridge or overnight oats, pancakes, breakfast muffins, and homemade energy balls and bars. 

The recommended intake for an 80 kg athlete, who is trying to maintain and build muscle is between 112-176 g (1.4-2.2g per kg). If they are not snacking throughout the day, then this athlete would have to include between 37 - 59 g of protein per meal which can  prove to be rather a lot. Not only is this practically difficult, in some people these incredibly high intakes can lead to gastrointestinal distress such as bloating or cramps. Therefore, consuming a protein shake between meals would be a successful strategy to help meet their daily protein requirements without needing these high intakes at each meal.


3. Satiety 

When it comes to satiety, some protein shakes will help to fill you up, while others will just add to your daily nutrition, depending on the type of protein you’re using and what you consume it with. For example, using a protein powder alongside frozen fruit and a healthy fat source, like peanut butter, could make a smoothie that is much more filling, while using it simply mixed with water isn’t so filling but still acts as a high protein snack. 

The content of protein shakes can also vary greatly, so make sure to check the label for calorie, fat, and sugar content to help you decide. Those that are higher in calories will be more filling than a low calorie or sugar-free version but you can always increase the calories of your shake (and protein levels too) yourself, by mixing it with milk instead of water.

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What type is best?

Protein powders can be made from either an animal source, including eggs and dairy-derived whey or casein protein, or a variety of plant sources like split peas, soy, brown rice, quinoa, pumpkin seeds, and hemp. 


Whey Vs Casein:

Whey protein comes from milk, contains high levels of essential amino acids (EAAs) and is easily digested and absorbed. Whereas, casein also comes from milk, has high levels of EAAs, but it is slower to digest.

 So, which is best? Whey and Casein can both be useful but can be used slightly differently. 

As your body digests and absorbs whey protein much quicker, supplementation with whey may well be a better option post-exercise compared to casein. Whey also contains more leucine – an amino acid crucial for building muscle - and some evidence suggests that it can help stimulate muscle growth more than casein, especially when consumed alongside or shortly after workouts (5, 6, 7).  

However, that isn’t to say that Casein doesn’t have it’s place. Given it is more slowly digested by the body, there is some suggestion it may be useful to consume pre-bed to minimize the risk of muscle protein breakdown overnight whilst we sleep.


Animal Vs Plant: 

Good news… plant protein powders are just as effective at building muscle. A 2019 study published in the journal Sports found that pea protein produced results on par with whey protein for muscle strength, performance, body composition, and muscular adaptations following eight weeks of high-intensity training. Also, a 2018 meta-analysis (combines the results of multiple scientific studies), concluded that soy protein supplementation leads to similar gains in muscle mass and strength in response to resistance exercise training as whey and animal protein supplementation did (8). 

The main difference with plant proteins is that they lack some EAAs and are therefore not considered to be complete protein sources. As a result, it would be best to consume a protein powder with a combination of plant proteins, such as pea and hemp, or brown rice and pea. Of course, taste preferences and sustainability can be important factors when choosing the right protein powder, so take the time to find what’s best for you. 


What to look out for when buying a protein powder?

  1. Be sure to read the ingredients list printed on the label. Simply put, the fewer, the better. Look for brands where the only ingredient is the protein itself, such as "pea protein isolate" or "sprouted brown rice protein." However, some plain powders do add probiotic and/or nutrients, such as vitamins and minerals, which may be beneficial for those who don't consume enough from other sources. Flavoured protein powders are okay but don’t forget that, even if you opt for an unflavoured protein powder, frozen or fresh fruit and/or nut butter can be used to sweeten and flavour the smoothie as well.

  2. A potential con is that protein powders are not regulated by the Food and Drug Administration (FDA), meaning they do not need FDA approval before they are sold to the consumer. It is therefore up to manufacturers to make sure their products are safe and accurately marketed, and there is no requirement they be tested to make sure they contain what the labels say they contain. For that reason, try to find a powder that’s been third-party tested by an independent company — such as Labdoor, NSF or Informed Choice. You can find their seals on the product label. Examples of third party tested protein powders in the UK are: The Protein Works, MyProtein, ISO 100, Garden of Life and Optimum Nutrition.


Are protein powders really necessary? 

Most people don’t need a protein powder to meet their RDI for protein and, with the right approach, can ensure they are obtaining enough from their diet. Whole, natural protein should always be the default, as it will contain more fibre than a powder and a wide range of other nutrients. Protein food sources like milk have been found to be just as effective as supplements, and there is no evidence to suggest that protein powders improve performance or promote recovery better than food sources. 

A simple change in foods such as Greek yoghurt in the morning with nuts and fruit, rather than plain breakfast cereal or muesli with milk, will help enhance the protein content of a meal. If you have a higher daily protein requirement, make your snack choices are also of higher protein content, e.g., edamame beans, roasted chickpeas, houmous and vegetable sticks or wholemeal pita. 

Having said that, in combination with other whole foods, a protein powder can offer a simple, convenient and safe way to help you meet your daily protein targets.


Bottom Line

  • Few people need to use protein powders to obtain sufficient protein intake, especially if consuming a wide, varied and balanced diet with plenty of whole food protein sources. However, protein powders can be a convenient and useful tool to ensure you are getting what you need when life makes planning and prepping a little more difficult.
  • Protein powders can absolutely  be part of a healthy, balanced diet—especially if it's been third-party tested and from a reputable provider.
  • Whether you opt for an animal or plant-based protein powder is up to the consumer. For different reasons, one may be more beneficial to you, whether that is cost, digestibility, or sustainability reasons. Fortunately, both have been proven to be effective in building muscle and aiding muscular recovery.
  • Try to spread your protein intake out across your meals and snacks and aim for a mix of different sources.
  • Ultimately find protein sources that suit your lifestyle, preferences, and taste, but where possibly try to include lots of variety.


Written by Abigail Attenborough (ANutr) & Florence Seabright

1) Schoenfeld, B.J. and 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, 15(1), pp.1-6.

2) Mettler, S., Mitchell, N. and Tipton, K.D., 2010. Increased protein intake reduces lean body mass loss during weight loss in athletes. Med Sci Sports Exerc, 42(2), pp.326-37.

3) Phillips, S.M. and Van Loon, L.J., 2013. Dietary protein for athletes: from requirements to optimum adaptation. Food, Nutrition and Sports Performance III, pp.37-46.

4) Nowson, C. and O'Connell, S., 2015. Protein requirements and recommendations for older people: a review. Nutrients, 7(8), pp.6874-6899.

5)  Miller, P. E., Alexander, D. D., & Perez, V. 2014. Effects of whey protein and resistance exercise on body composition: a meta-analysis of randomized controlled trials. Journal of the American College of Nutrition, 33(2), 163–175. 

6)  Morton, R.W., Murphy, K.T., McKellar, S.R., Schoenfeld, B.J., Henselmans, M., Helms, E., Aragon, A.A., Devries, M.C., Banfield, L., Krieger, J.W. and Phillips, S.M., 2018. A 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, 52(6), pp.376-384.

7) 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 (Bethesda, Md. : 1985), 107(3), 987–992.

8) Boirie Y, Dangin M, Gachon P, Vasson MP, Maubois JL, Beaufrère B. Slow and fast dietary proteins differently modulate postprandial protein accretion. Proc Natl Acad Sci U S A. 1997;94(26):14930-14935. doi:10.1073/pnas.94.26.14930

9)  Messina, M., Lynch, H., Dickinson, J.M. and Reed, K.E., 2018. No difference between the effects of supplementing with soy protein versus animal protein on gains in muscle mass and strength in response to resistance exercise. International journal of sport nutrition and exercise metabolism, 28(6), pp.674-685.


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