Protein has gained a reputation for being the most important macronutrient for building muscle, and while it’s true that protein is an essential building block for building and maintaining muscle mass, increasing your protein intake will not necessarily help you to preserve muscle if you’re already meeting your body’s needs. In fact, there are other foods that may be more beneficial for preserving muscle.
Due to the sheer number of calories that athletes need to support their training, most consume more than enough protein to promote muscle growth. In fact, studies have shown that consumption of protein higher than 1.7 gram/kg of bodyweight per day is more than the body can absorb and the excess will simply be oxidized for energy. For a 70kg (154lb) athlete, that would be only 120 grams of protein per day. If this athlete is consuming 3,000 calories per day, this would only represent 16% of his or her daily calorie requirements.
Current recommendations for athletes range from 1.2-1.7 g/kg of bodyweight per day. Most athletes will easily meet or surpass this protein requirement without any effort. That means athletes could be better off consuming other foods (carbohydrates and fats) which are a more efficient fuel source to support endurance training rather than increasing protein intake above these levels.
Acidic Foods and Muscle
Not only is there no additional benefit to over-consuming protein, but there may be a detrimental effect on the muscles. High protein foods are more acidic, and can lead to muscle breakdown if eaten in large amounts.
The acidity of a food is determined by the amount and type of amino acids that are present in a food. When your body metabolizes these amino acids, hydrogen ions are released and these contribute to an acidic environment in your body. Phosphorus, which is found in high amounts in animal products, also causes acidity in the body.
There is a strong correlation between the acidity of foods that you eat and muscle turnover. When you consume acidic foods, your body must mitigate the acid load in order to maintain a stable environment. Your body excretes this acid by increasing the production of ammonia. Ammonia attracts the acidic hydrogen ions and bonds with them, before being excreted in the urine as ammonium, thus removing the acidic ions.
Ammonia is formed from amino acids, most importantly glutamine. Skeletal muscle is rich in these amino acids. When your body increases production of ammonia, it will break down muscle in order to get these ingredients. The more acidic your diet is, the more ammonia your body will need to generate to mitigate the acidity. This will create a higher likelihood of muscle breakdown.
Many athletes are familiar with sarcopenia, the age-related loss of muscle mass. There are a lot of reasons this happens, but one thing that is clear is that nutrition plays a significant role in the rate of decline. Kidney function gradually declines with aging, and your body will be less effective at removing the acidic hydrogen ions that can build up with an acidic diet.
Herein lies the paradox. The foods that are highest in protein can actually contribute to a breakdown of muscle if over-consumed. Lots of these acidic foods contain vital nutrients and are important components to a balanced diet.
Offsetting the Acidity
Of course it’s unrealistic, and even unhealthy to eliminate all of the foods that are considered acidic. Grains provide a vital source of fuel for endurance exercise and it can be difficult to consume enough calories if these are eliminated. Some meat and fish contain a quality source of protein that your body requires (in moderation) as well as bioavailable forms of iron, B vitamins, and omega 3s.
So what’s the answer? Fruit and Veggies!
Just as some foods are acidic, others are alkaline. These foods have the opposite effect and will counteract the acidic foods. Most alkaline foods are either fruits or vegetables. A food derives its alkalinity from the amount of potassium, magnesium, or calcium that it has. Fruits and vegetables are abundant sources of these nutrients.
By incorporating fruits and vegetables in your meals throughout the day, you can offset the acidic foods and maintain a balanced pH. An easy way to envision how this works is by something called the Potential Renal Acid Load (PRAL).
The PRAL determines the potential acidity of a food. It is calculated as follows:
PRAL = (0.49 x grams of protein)
+(0.037 x mg phosphorus)
– (0.021 x mg potassium)
– (0.026 x mg magnesium)
– (0.013 x mg calcium)
As you can see from the equation above, acidic foods high in protein and phosphorus will be acidic. A food that is low in protein and contains lots of potassium, magnesium, and calcium will have a negative acid load and counteract an acidic food.
Almost all fruits and vegetables will have an alkalizing effect. Beans are also alkaline and a great source of protein.
The Argument For a Plant-Based Diet
Now I’m not suggesting that you go full-bore vegan, but reducing consumption of animal products and increasing consumption of plant-based foods is a simple way to improve the alkalinity of your diet.
A 3-year study on elderly adults found a strong correlation between potassium levels and muscle retention. Over the 3-year study, individuals with above-average potassium intake had 1.64kg more muscle mass than cohorts who had half of that potassium intake. This is almost equal to the average amount of muscle mass lost per decade due to sarcopenia in people over 50. The high-potassium group had muscles of someone 10 years younger so to speak.
In another study, rats were fed the exact same amount of calories, but one group was also administered an acid in the form of HCl. In very short order, the acid-load rats began to excrete high levels of nitrogen. The acid-load rats only gained one-third the amount of weight as the control group. By the end of the 15 day study. The acid-load rats weighed 15% less than the control rats.
Replacing animal proteins with plant-based proteins is an effective strategy for improving alkalinity. Studies have shown that as your ratio of plant to animal foods increase, your acidity decreases.
Of the animal proteins that are the least acidic, milk and yogurt are acid-neutral. This is because the calcium in these foods neutralizes the acidity.
How to Improve Alkalinity
There are a few easy modifications you can make to improve the alkalinity of your diet. These will go a long way in helping you to build and maintain your hard-working muscles.
Counterbalance Animal Proteins: If consuming a meal that contains a high acid load, like meat or cheese, consume some alkaline foods to offset this. An example could be eating a big salad with your protein.
Replace Some Grains With Fruit
As athletes, we need a lot of calories to keep the engine going strong and grains provide a great source of this fuel. However, fruit can also be a great source of carbohydrate to fuel your training. Consider replacing some of your grains with fruit.
Trade Animal Protein For Plant Protein
Plant-based diets are becoming increasingly popular among athletes for a multitude of reasons. Look for ways throughout the day that you can decrease your consumption of meat and eggs and replace them with plant-based sources. Plant-based proteins have a much lower acid-load than animal proteins. Consuming any combination of greens, grains, or legumes will give you all essential amino acids.
Reduce Overall Protein Intake
Given that most athletes have no trouble consuming the recommended amount of protein per day, it is possible that you may benefit from reducing your protein intake. Track your calories for a few days to see what your protein intake is like. If you’re well over 2 grams per kilogram of bodyweight per day, consider reducing your portion sizes of protein. You can replace these calories with carbohydrates and fats, which will be better suited to fuelling endurance performance and will improve the alkalinity of your diet.
The mantra “everything in moderation” also rings true for protein. Some protein is good, but more isn’t necessarily better. While protein is the building block for muscle, many other key nutrients also play a role in achieving optimal muscle health. The one big takeaway: eat your veggies!
References
Angéloco, Larissa Rodrigues Neto, et al. “Alkaline Diet and Metabolic Acidosis: Practical Approaches to the Nutritional Management of Chronic Kidney Disease.” Journal of Renal Nutrition, vol. 28, no. 3, 2018, pp. 215–220., doi:10.1053/j.jrn.2017.10.006.
Dawson-Hughes, Bess, et al. “Alkaline Diets Favor Lean Tissue Mass in Older Adults.” The American Journal of Clinical Nutrition, vol. 87, no. 3, 2008, pp. 662–665., doi:10.1093/ajcn/87.3.662.
Schwalfenberg, Gerry K. “The Alkaline Diet: Is There Evidence That an Alkaline PH Diet Benefits Health?” Journal of Environmental and Public Health, vol. 2012, 2012, pp. 1–7., doi:10.1155/2012/727630.
Tannen, Richard L., and Sithiporn Sastrasinh. “Response of Ammonia Metabolism to Acute Acidosis.” Kidney International, vol. 25, no. 1, 1984, pp. 1–10., doi:10.1038/ki.1984.1.
Tipton, Kevin, and Robert Wolfe. “Protein and Amino Acids for Athletes.” Journal of Sports Sciences, vol. 22, 2004, pp. 65–79.
Williams, Bryan, et al. “Skeletal Muscle Degradation and Nitrogen Wasting in Rats with Chronic Metabolic Acidosis.” Clinical Science, vol. 80, no. 5, 1991, pp. 457–462., doi:10.1042/cs0800457.
