High Protein and You

Everyone knows what "protein" is and/or has at least heard about it. Most lifters or those who exercise know in some capacity that they need to be taking in protein (hopefully). However, not everyone knows why, how it affects us, and how much exactly we need to consume. Lets talk about it...

What is Protein?

Protein is a macronutrient. It is one of three unless you're in college then we can include alcohol as well making it four. In layman's terms, protein is a necessary building block for muscle formation. It is "the building block". We won't get too sciency on this as it's not quite pertinent to this topic. However amongst the macronutrients: protein, carbohydrates, and fats; protein stands out as a builder whereas carbs and fats are fuel sources for energy. Where do we get protein from? Well, milk products, beef, poultry, pork, legumes, nuts, fish etc. There is a caveat to this as almost every food product contains some amount of protein. However, to ensure efficient and optimal protein utilization (protein synthesis) we need to seek out quality proteins. Quality proteins contain all nine essential amino acids which are what a protein is made out of. When our body uses protein or any nutrient it breaks it down into its components. Protein is broken down into its amino acids. These essential amino acids are necessary for protein synthesis. See what I'm getting at? Most "quality" protein sources (as listed above) will contain all the essential. Its when you get into the grey areas such as peanut butter which on the label has "protein" however, it does not have all the essential amino acids. Meaning it is not a complete protein. If you prioritize quality proteins in your diet then you needn't worry too much. Vegan and vegetarian diets need to consider optimal protein intake and seek out rich plant-based protein sources. Also, collagen protein is not a complete protein. Therefore should not be considered as a quality protein source. However, it is an important supplement but should not be treated as your typical protein powder. 

 

High Protein and Muscle Mass

Currently, the daily recommended dose (RDA) for protein intake is set at 0.8 grams per kilogram of body weight per day (.8g/kg/d). This is what the American College of Sports Medicine (ACSM) recommends you take in per day for everyone at a minimum. However, everyone should be exercising and therefore we are here to argue the benefits of a higher protein diet. Which would be above the RDA. A high protein diet is defined as greater than (>).8g/kg of body weight. There are many benefits to a high-protein diet but the three main points I want to discuss are: that high-protein diets help with the preservation and increase of lean mass (and loss of fat mass), provide context to the concern about kidney function, and lastly its usefulness to athletic populations.

The main point is the preservation and subsequent increase of lean body mass (muscle) and loss of fat mass (pudge) in conjunction with higher amounts of protein. The studies I examined varied in what was considered “high protein” but all of which were above .8g/kg/d. I chose to utilize a definition of >.8g/kg/d to include a larger majority of studies with varying doses of protein consumption. Longland et al., (2016) examined the effects on lean body mass increases in their high protein group who consumed 2.4g/kg/d. The study examined lean body mass amounts of (40) young men (23yrs +/- 2) during a period (4 weeks) of hypocaloric (calorie deficit) intake (~40% reduction) and an intense exercise regimen of resistance training combined with high-intensity interval training 6 d/wk. Though this study's “low protein group” (1.2g/kg/d) was still higher than "my" set definition of high protein, it shows a cumulative benefit to higher protein beyond marginal increases in protein intake. The high protein shows benefits to body composition in older obese subjects as well. In Verreijan et al., (2017), found greater increases in fat-free mass for their group that utilized high protein and resistance training exercises. However, the other two groups: one being high protein without exercise and the other being low protein with exercise found no significant interaction with body composition.

What does this mean? Well, consuming higher protein amounts when in a calorie deficit can help to preserve and in some cases increase muscle mass while losing fat. Pretty fricken badass right? In regards to the other studies which includes another type of population which is unfortunately very common in the U.S., obese individuals, showed basically the same as the other study; that high protein in conjunction with exercise had a greater increase in lean mass. The implications of this are more so than building muscle under the layer of fat as muscle is more metabolically active than fat. Meaning the more muscle you have the more calories you burn. For obese individuals, this means consuming higher protein while exercising on your weight loss journey will help to speed up that loss however slightly but ounces make pounds.

 

Hold up! Too much protein is bad for your kidneys right?

You may or may not have heard this myth before about too much protein being hard/bad for the kidneys. In Ko et al., (2020) they examined the correlation between high-protein diets and chronic kidney disease (CKD) through its pathology (cause of CKD) and the effects of high protein on the body. There isn’t a direct causation between dietary protein and chronic kidney disease but it has been identified as a possible correlation. However, there is a caveat to the information. The study just demonstrated that those already at risk for CKD are potentially at more risk of developing CKD. So otherwise healthy individuals have a limited-no risk of developing CKD due to a high protein diet. That being said, it is a potential element to look out for in CKD-prone individuals. The populations to keep an eye on are: obese, older-age, those with previous kidney disease, and those with heart disease to name a few. These are already our "special populations" that require special consideration in dietary and lifestyle choices because of the risks they have. Another study by Juraschek et al., (2013) examined the effects of different diets on heart and organ function/health. The three diets each emphasized one of the three macronutrients. The study found that the high protein diet (25% of kcals from protein) increased the estimated glomerular filtration rate (eGFR), or how well the kidneys are filtering, which is associated with chronic kidney disease. However, this study's participants were all prehypertensive or at stage 1 hypertension which in itself is a major contributor to kidney disease. Therefore, it is inconclusive on whether a high protein diet puts normal healthy populations at a relevant risk for kidney disease. This means that if you're already an individual at risk for kidney disease then anything that affects the kidneys to a degree is something to be cautious of and requires consideration when implementing dietary changes and those individuals should consult professionals.

 

High Protein and Athletes

 

The requirements and effects of a high-protein diet tend to be different for resistance-trained individuals (People who lift). In a study published by the Journal of the International Society of Sports Nutrition, it states that “according to the Position Stand by the International Society of Sports Nutrition, intakes of 1.4-2.0 g/kg/d are needed for physically active individuals,”(Antonio et al 2014). This recommendation is already set at 0.6 - 1.2 g/kg more than the RDA. However, in this study conducted by a group from Nova Southeastern University, they set out to test how consuming 4.4 g/kg of body weight would affect body composition. Over a period of 8 weeks, the study group consumed an average of 307 grams of protein per day and exceeded their daily caloric intake by an average of about 800 calories. This group utilized higher protein amounts as a means to put test subjects into a caloric surplus. When the trial period ended the group of researchers compared the pre and post-results in body composition. They found that there were no significant changes in body composition for either the high protein group or the control group. It is worth noting that the control group consumed 1.8 g/kg of protein in relation to their body weight and that the groups were told not to change any other eating or training habits. What makes the results of this study relevant is the fact it shows as the study states “this dispels the notion that 'a calorie is just a calorie’” (Antonio et al, 2014). There is often an argument against a high protein diet as some believe that it will just promote a greater caloric intake, and cause health problems. However, this study showed that despite the caloric surplus they did not increase in fat mass when compared to the control group. This is looking at the other side of high protein consumption in our hypercaloric diets. In another study published in April 2022 in the Journal of the International Society of Sports Nutrition, another group of researchers from Nova Southeastern University decided to follow up on the earlier study and determine if there would be significant changes in body composition if they again adjusted protein intake, but also changed their training regiment this time around. At the completion of their study, the research group found that “the HP (high protein) group lost an average of 1.6 kg of fat mass versus 0.3 kg in the NP group. Moreover, the percent body fat decrease was −2.4 % and −0.6 % in the HP and NP groups respectively,” (Antonio et al, 2022). This point stands out to such a great degree because, like this group’s last study, the high protein (HP) and the normal protein (NP) groups had similar results for increases in fat-free mass. However, where this study differentiates is in the loss of fat mass in the HP group. While eating roughly an extra 400 calories per day, the HP group had a notably greater loss of fat mass. This can be accredited to the fact that in comparison to the last study, they increased the training load, which then increases metabolic needs and muscle protein synthesis in the test subjects and would be a likely reason as to why there was fat mass lost. 

Additionally, there is evidence supporting the idea that a high-protein diet can help support athletic performance and safety. For endurance athletes, this comes in play when attempting to avoid respiratory issues, as discussed by Cintineo H. et al. (2018) “A diet providing a daily protein intake of 3 g/kg, including 60 g/day of casein protein, is sufficient in returning circulating immune cell levels to those seen during lighter training periods, while a diet providing a daily protein intake 1.5 g/kg did not result in enhanced immune cell levels,” (Cintenio et al, 2018). This information which they got from Kephart et al., demonstrates that protein also has benefits for endurance-focused training. In the form of maintaining (to a degree) immune function which can be compromised during longer endurance events.

 

TL;DR: High protein diets are generally safe and effective in preserving or improving muscle mass when implemented with exercise.

References

Antonio, J., Peacock, C., Ellerbroek, A., Fromhoff, B., & Silver, T. (2014). The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. Journal Of The International Society Of Sports Nutrition, 11(1). doi: 10.1186/1550-2783-11-19 

Antonio, J. (2022, April 1). A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women – a follow-up investigation. Taylor & Francis. Retrieved April 4, 2023, from https://www.tandfonline.com/doi/full/10.1186/s12970-015-0100-0

Cintineo, H., Arent, M., Antonio, J., & Arent, S. (2018). Effects of Protein Supplementation on Performance and Recovery in Resistance and Endurance Training. Frontiers In Nutrition, 5. doi: 10.3389/fnut.2018.00083 

Juraschek, S. P., Appel, L. J., Anderson, C. A. M., & Miller, E. R. (2013, April). Effect of a high-protein diet on kidney function in healthy adults: Results from the OmniHeart Trial. American journal of kidney diseases : the official journal of the National Kidney Foundation. Retrieved April 4, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3602135/   

Ko, G.-J., Rhee, C. M., Kalantar-Zadeh, K., & Joshi, S. (2020, August). The effects of high-protein diets on kidney health and longevity. Journal of the American Society of Nephrology : JASN. Retrieved April 4, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7460905/  

Longland, T. M., Oikawa, S. Y., Mitchell, C. J., Devries, M. C., & Phillips, S. M. (2016). Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: A randomized trial. The American journal of clinical nutrition. Retrieved April 2, 2023, from https://pubmed.ncbi.nlm.nih.gov/26817506/  

Verreijen, A. M., Engberink, M. F., Memelink, R. G., van der Plas, S. E., Visser, M., & Weijs, P. J. M. (2017, February). Effect of a high protein diet and/or resistance exercise on the preservation of fat free mass during weight loss in overweight and obese older adults: A randomized controlled trial. Nutrition journal. Retrieved February 27, 2023, from https://pubmed.ncbi.nlm.nih.gov/28166780/