Brett Williams FNP, CPT

We have heard a lot recently about the role of protein. Just look around and you will see everyone advertising and promoting its benefit. We have protein chips, shakes, cookies, juice, powder etc. Some people claim we should only eat protein and nothing else. So, what is so special about protein? The intent of this article is to provide a non-biased review of what the literature says about protein in relation to physical fitness, muscular strength and general health. We will review why we need protein, the types of protein available, how much protein we need, when to consume protein and how to find reputable sources of protein.  By the end of this article, the reader should have a basic understanding of what to look for when trying to start protein supplementation.

Why do We Need Protein

Proteins are critical for a variety of important functions within the human body. Some of these important functions include synthesis and repair of cells, structures, tissues and muscles. Other important functions include development and transport of hormones, enzymes and antibodies. Proteins are the “building products” of all cells and tissues. Under certain conditions, we can even use proteins to create energy however carbohydrates are much better at doing such.

In the context of fitness and body composition, proteins are a very important part of our diet. A systematic review involving 49 different trials and a population of 1,863 participants involved in resistance training 2 times weekly for 6 weeks or longer found that protein supplementation in a diet not calorie restricted, significantly increased strength, lean body mass and muscle size. (Morton et al., 2018). Average lean muscle gains of 27% were noted and increased cross-sectional muscle fiber areas increased 38%.

What types of Protein do We Need

Proteins are found in both plant and animal sources. Proteins are big bundles of small molecules called amino acids. Proteins differ based on the combination of amino acids used to build them. When we eat proteins, they are broken down into these small molecules then distributed throughout the body to repair tissues. All proteins are made up of varying combinations of these different amino acids. In fact, there are only 20 amino acids that are used to make up proteins. Our bodies are capable of synthesizing and converting eleven of these on their own; however, the remaining nine can only be obtained through dietary intake. These nine are called “essential”.  

Our bodies are constantly breaking down proteins, taking these amino acids and building new proteins. This process is known as protein turnover. During this process, it is quite important that we are continuing to supply our bodies with “new” sources of amino acids so we can keep building new proteins. This is a big problem with calorie restriction diets. If we decrease our carbohydrate / calorie intake such that we are utilizing amino acids / protein for energy sources, we can’t repair and build tissue adequately thus start to lose lean muscle mass – hence the common problem with the GLP-1 type drugs.

Animal (meat, poultry, seafood, dairy), Soy and Hemp based protein sources are considered “complete” meaning they have all 20 amino acids.  All other plant-based proteins are considered “incomplete” and lack the essential nine amino acids.

When we are discussing fitness training and muscle synthesis particularly, we need to look closer at the types of amino acids we are consuming. Leucine is one of the nine essential amino acids that we can only get from our diets. Leucine is the primary trigger for muscle protein synthesis. Milk based protein (whey and casein) have the highest percentage of Leucine of all proteins (roughly 11 and 9% by content).

Whey protein powder is a common source of protein supplementation due to its high source of quality protein, easy digestibility and ease of mixing with other products such as milk / water / juice. Whey protein powder is found in three forms: Isolate, concentrate and hydrolysate. Whey protein Isolate contains 90% protein and undergoes an ultra-filtration process to remove fat and carbohydrates. Whey protein concentrate contains 80% protein with small amounts of fat, carbohydrate and lactose (naturally occurring sugar found in milk). It is usually the least expensive, however most problematic on digestion, especially in those with lactose intolerance. Whey protein hydrolysate undergoes additional refinement by adding enzymes which start to break down the amino acids into shorter chains prior to you consuming them. This reportedly improves the digestion and absorption of the proteins consumed. This additional process comes at an additional price.

Casein protein is the other form of protein found in bovine milk. It has a lower percentage of Leucine than whey and is insoluble in acid thus “curdles” once it reaches the stomach. This tends to slow its digestion and as such, decreased protein muscle synthesis as compared to whey products. Several studies have been done looking at casein protein vs placebo prior to going to bed and have found increased muscle synthesis in those that consume casein prior to sleep. (Snijders et al,, 2015)

How Much Protein Do We Need and When Do We Need It

The recommended daily allowance (RDA) for protein consumption per the US government is 0.8 gm/kg/day of body weight. Since that time, numerous studies have been conducted looking at that level in conjunction with muscle protein synthesis in fitness training programs. Recent evidence indicates that higher-than-recommended amounts are linked to increased muscle mass and better body composition in adults of all ages and training backgrounds.  (Aragon et al., 2017)

The international Society of Sports Nutrition recommends daily protein intake of 1.4-2.0 gm/kg of body weight per day split every 3-4 hours throughout the day. Muscle protein synthesis remains elevated for up to 24 hours after resistance training thus a steady supply of protein intake throughout this time tends to provide better results. (Cintineo et al., 2018)

Where Do We Find Protein Supplements

Just go to your local grocery store and look around, protein supplements dot the shelves. First, we need to understand that all proteins are not equal. Start by reading the label – ensure the source is a quality animal or soy-based product with all essential ammino acids. If you choose a whey based, look at the ingredients to see the form such as whey concentrate, isolate or hydrolysate. Look at the calorie content and added ingredients such as fats / sugar / preservatives. Meat products like salami or pepperoni sticks are often advertised as “high in protein,” but their high levels of unhealthy fats and calories can hinder efforts to improve body composition.  For supplementation purposes, it is probably best to stick with whey or soy powder. These are high in quality proteins and often are not laden with extra calorie fillers. It is important to understand, however, that protein supplementation should be just that, supplementation. We should have a balanced diet of fruits, vegetables, quality proteins, healthy fats with minimal additives, preservatives and simple sugars. We should then use supplementation between meals to bump up our 24-hour protein intake goal if needed.

Currently, we are at the mercy of the protein manufacturer to provide honest data regarding protein content printed on the food label. If you are concerned about that, you can look for an “NSF” stamp of approval. The NSF (National Sanitation Foundation) was founded in 1944 and is a non-profit organization that provides third party testing to ensure accuracy of food products sold. When dealing with high dollar protein supplements, it would be wise to ensure you are consuming what you intend to consume. Products can also be researched further by going to www.nsf.org

Current research indicates that fulfilling daily protein intake requirements is essential for both the maintenance and development of muscle mass.  By understanding this process, knowing what sources of protein and where to find quality protein, we can reward our hard work in the gym by creating an environment that will maximize our bodies recovery.

Resources

Aragon, A.A., Schoenfeld, B.J., Wildman, R., Kleiner, S., VanDusseldorp, T., Taylor, L., Antonio, J. (2017, Jun.). International society of sports nutrition position stand: diets and body composition. Journal of the International Society of Sports Nutrition, 14(16)

Cintineo, H.P., Arent, M.A., Antonio, J., Arent, S.M. (2018, Sept.). Effects of protein supplementation on performance and recovery in resistance and endurance training. Frontiers in Nutrition, 5(83).

Morton, R.W., Murphy, K.T., McKellar, S.R., Schoenfeld, B.J., Henselmans, M., Phillips, S.M. (2018, Mar.). A systematic review, meta-analysis and meta-regression of the effects of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376-384

Snijders, T., Res, P.T., Smeets, J.S., Van Vliet, S., Van Kranenburg, J., Maase, K., Van Loon, L.J. (2015, Jun) Protein ingestion before sleep increases muscle mass and strength gains during prolonged resistance-type exercise training in healthy young men. Journal of Nutrition, 145(6), 1178-1184