Let’s start at the end… One of the primary contributors to a shorter lifespan is sarcopenia, or more simply, low muscle mass and strength. As we become frail, we lose the ability to handle life’s simple everyday tasks, risking the loss of independence and requiring long-term care. With sarcopenia, we are at risk of falls and fractures, and through complications, even death.
Approximating the loss of muscle mass at a rate of 3-8% per decade after the age of 30 (and up to double that after 60)[ 1 ], with a greater portion being fast-twitch fibers—those that can help us quickly post up to save us from a fall. With age working against us, it’s not easy to stay fit, active, and vital later in life, so we need all the help we can get. Apart from the obvious – exercise, leveraging protein can be a very helpful tool.
Exercise can be as complex as one desires, but we’ll keep it simple here. Any kind of exercise is beneficial, especially when the alternative is no exercise. However, resistance exercise or strength training yields the most effective results.
What is protein?
Protein is one of the macronutrients in our diet. They are large molecules that comprise of amino acids. The simplest description of an amino acid is that it is an organic compound containing mainly carbon, oxygen, hydrogen, and nitrogen. Of the 22 amino acids (20 common ones and 2 non-standard ones) that make up protein, 9 are essential, meaning our body can’t make them. Therefore, we must obtain them through food, or… stuf goes wrong. The type and order of amino acids give protein its structure and function. During the digestion process, protein is broken down mostly into single amino acid constituents, rarely do 2 or 3 amino acids stay together and get absorbed in that form.
When it comes to dietary protein and muscle protein synthesis, the outline is as follows:
1. Consume between 1.6 to 2.4 grams of protein per kilogram of body weight. [ 2, 3, 4]
2. Avoid trickling it out during the day; instead, aim to consume between 30 and 50 grams per meal, especially during breakfast and dinner. [ 5, 6, 7]
3. Opt for high-quality protein, with animal protein being superior to plant protein in terms of digestibility, bioavailability, and amino acid profile.
These points are somewhat less important for children or teenagers going through puberty when muscle protein synthesis is driven by hormones (sex hormones, IGFs, and insulin) and is more sensitive to smaller amounts of protein per meal. Additionally, the recycling of amino acids within the body is more efficient during periods of growth.
How much protein do I need?
The official recommended dietary allowance is 0.8g of protein per kilogram of body weight (0.36g per pound). This number is for basic bodily function upkeep, without stress factors acting on the body. It is measured using something called nitrogen balance, which essentially measures how much protein we need to replace the protein we degrade and consequently expel, losing it as nitrogen. This method tends not to be very accurate, often underestimating the amount we actually lose. So if we lose more, we need to take in more just to maintain balance, let alone grow new tissue. In scenarios of regular intense exercise, caloric deficit, or even illness where we are in a catabolic state, we should be looking to double that number or go up to 1.8 to 2.2g of protein per kilogram of body weight.
How to distribute protein during the day…?
To leverage the effects of amino acids (almost exclusively Leucin) triggering muscle protein synthesis, we need between 30 to 50g of protein per meal. We can absorb more, basically all the protein we consume during a meal, but exceeding this 30 to 50g mark won’t prompt an even greater muscle protein synthesis response, with the excess being ‘burned’ as energy. The amount one can effectively utilize varies based on individual size, muscle mass, and the muscles being trained. Additionally, age plays a role, with increased protein needs as we age due to anabolic resistance.
Determining the quality of a protein source…
In general, animal protein is more effective than plant protein in triggering a muscle-building response. The reason is that plant protein is assembled in fibrous structures in the plant and is therefore harder to digest. As a result we get fewer free amino acids in our gut at our disposal (from 30 to 50% less bioavailable). Another factor is the amino acid profile of plant protein. It is usually less rich in amino acids conducive to triggering muscle protein synthesis (Leucine) and in essential amino acids in general. It’s not to say that you can’t get enough of the aforementioned amino acids by increasing the total amount of plant protein, but that brings with it the rest of the plant, which means we’re probably going to overconsume calories in the process. For individuals following plant-based diets, one consideration is to supplement with isolated plant protein (pea, corn, soy, or potato protein isolates), which have bioavailability similar to animal protein. This allows you to increase your protein intake while maintaining better control over your caloric intake.
Conclusion…
Protein should not be calculated as a percentage of daily calories; rather, it should be a fixed number of grams per day, and other macronutrients should be adjusted accordingly to fit our caloric budget.
Don’t think that you can get jacked or stave off sarcopenia with just protein; by itself, it’s just a nudge in the right direction. Resistance exercise is a much greater thrust towards building muscle, with protein, in this case, being that top-shelf jet fuel getting the engine humming just right.