Protein Needs for Marathon Training

The phrase “Not all calories are created equal” has been passed around quite a bit on social media recently. This phrase became popular with the trend of high protein diets, and its meaning can be traced to the purpose of the 3 macronutrients in our body. We have adequately discussed the role of carbohydrate and fat in the diet as sources of energy. Both of these macronutrients have a caloric value, which measures their value as energy expended. Carbohydrate is almost exclusively used for energy, while fat is used for energy along with a variety of processes in the body. Even with variance in purpose, both carbohydrates and fat are our body’s primary energy sources to fuel activity. Protein, the third macronutrient, does not follow suite. While protein also has a caloric value, it is not used primarily for fuel. In fact, a majority of the protein in our diet is destined to serve as a building block for new tissue like muscle, hair, skin, and fingernails, or in the creation of a variety of hormones and neurotransmitters. The body can use protein as energy when carbohydrates and fat are not present in adequate quantity, but the dominant role of protein is the creation of new tissue, so much so, it is often referred to as a secondary energy source. With so much time devoted to fueling and maximizing performance during training thus far in the blog, it makes sense to properly address recovery, and with it, protein.

The simplified physiology of all exercise is intentional muscle strain. In the case of running, most of this strain is in the legs, and it occurs in a gradual manner which promotes certain muscle cells to flourish. Each time you run, you challenge the muscle tissue. As duration and intensity increase, the muscle tissue becomes overstrained and tears slightly. This stress sparks a response in the body to repair and rebuild. The goal of this response is to build the tissue stronger so when presented with that stress again, it is ready to handle the strain. Repeating this mild stress with adequate rest is what we refer to as building muscle. Nutritionally, there is a lot involved including carbohydrates, vitamins, minerals, and you guessed it, protein. Protein serves as the building block of the new tissue. Without adequate protein, the stressed muscle will not recover adequately, and will not grow back stronger and more resilient. To ensure adequate recovery, we need to make sure you consume adequate protein!

The current recommendations for protein in endurance athletes is 1.2-1.4 grams per kilogram body weight. To determine your needs, divide your weight in pounds by 2.2 to get kilograms. Next multiply that number by 1.2 and 1.4 to get the adequate protein range. For those trying to build muscle, 1.5 to 1.7 g/kg is recommended. The earlier range is associated with recovery of existing tissue, and does not offer excess protein for new tissue development. This does not mean you won’t get faster or stronger, but does place a limit on the amount of fat free mass your body will build. In endurance athletes, too much muscle mass can hold back a runner, which is the reasoning for the recommendations above.

Once you establish your daily protein needs, the next step is to optimize the intake throughout the day. I recommend intake being broken into 4-5 meals per day to promote the absorption of protein. Eating smaller amounts of protein throughout the day allows you to better absorb the meal you are taking in, especially in athletes who need more protein than less active individuals. Each meal should contain a similar amount of protein, with a slightly larger portion in the evening. An example for those eating 4 meals per day is to eat 0.3g/kg per meal, and 0.4g/kg in the 4th meal of the day. This spread will optimize intake and promote recovery of strained muscle tissue.

Protein is very easy to get from a variety of sources. We place emphasis on meats because they are the most concentrated source of protein, but it is by no means necessary to eat meat, especially in endurance athletes. Foods like lentils, quinoa, seitan, tofu, nuts, seeds, beans, amaranth, and other grains (both modern and ancient) contain protein that contribute toward your daily needs. Most of the sources listed are also a fat or carbohydrate source, which for endurance athletes may be beneficial in overall calorie consumption and recovery. Meat does provide iron, B12, and B6, so those with a vegetarian diet should assess their intake of these items when evaluating their diet for short-term and long-term success.

To ensure proper recovery, make sure you are getting enough protein. A variety of sources can supply your body with enough protein to recover muscles, and prepare you for your next training session. Use the protein guidelines to establish your daily need, and spread the protein out in a way that allows for proper digestion and absorption. Finally, evaluate what micronutrients you might be lacking as a result of dietary restrictions, and assess the options to reach adequate consumption of them.

Here is to a safe recovery!

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