There have been many conflicting conclusions in the past about the appropriate amount of protein needed by the body to support lean muscle tissue growth and repair, especially if you are an athlete in training.
Proteins are made up of amino acids – the so-called the building blocks of life - that serve to stimulate muscle growth and protein synthesis, as well as support immune function and much more. There are two types of amino acids: essential (EAAs) and non-essential (non-EAAs). The body can synthesize non-EAAs (the body can produce these on its own), while EAAs must be acquired from the diet.
According to research examining protein requirements for strength training from the National Strength and Conditioning Association, in order for the body to reach protein equilibrium, synthesized protein (EAAs) needs to restore the “continually degrading body protein.”
If the body does not receive adequate amounts of EAA’s and non-EAAs to balance the equation, “the rate of protein synthesis (manufacture) cannot match the rate of protein degradation (breakdown).”
Roughly translated, there would be insufficient amounts of dietary protein to match the body’s internal amino acid expenditure for growth, repair, immune function support, etc.
For example, strength athletes may require 1.2–2.0 grams of protein/kg of body weight, while endurance athletes may require 1.2–1.4 grams of protein/kg of body weight. These formulas consider total body weight, which is standard in the industry.
In my opinion, daily protein requirements should be based on lean body weight (fat free weight), as opposed to total body weight, which includes, muscle mass, organ tissue, bone, fat and fluid. In other words, why would I feed fat tissue protein?
In order to accurately define your own lean body mass, a DXA scan is a “gold standard” way to determine body composition. DXA (Dual X-ray Absorptiometry) scans use sophisticated, low radiation (it actually exposes the individual to less radiation than compared to the 60-80 millirems in a normal chest X-ray) X-ray technology to measure bone mineral density. However, in my program, The Fitness Principle at East Jefferson General Hospital, we use the DXA Scan to measure overall body composition as well.
Our nutritionist, Jodie Muhleisen, who is certified in sports nutrition, says, “The DXA will provide the amount of lean (muscle) mass down to the gram. This is very important in determining protein requirements for an individual.” Taking into account an individual’s activity level, Muhleisen says, “for someone very active engaging in physical activity (including cardiovascular and resistance training) on most days of the week, they would require 1 gram of protein per pound of lean mass.”
Using myself as an example, my DXA scan last year pegged me at 8 percent body fat and 92 percent lean, at a scale weight of 148 pounds. My protein requirement, using Muhleisen’s formula for a very active individual such as myself, would be 136.16 grams of protein per day, which is my target.
Muhleisen also uses a resting energy expenditure (REE) test to learn how many calories a day you are burning while at rest, which is a product of your lifestyle. This number is roughly equal to 65 percent of your total daily energy expenditure. Once you have determined that level, Muhleisen uses an estimation of the energy expenditure from daily physical activity, and the thermal effect of eating (TEE) to design a healthy, workable meal plan based on an individual’s specific goals.
As a general rule of thumb, outlined in my book "Lean & Hard: The Body You’ve Always Wanted in Just 24 Workouts," a novice athlete should consume roughly 20 grams of protein immediately after resistance exercise. Also important to add with protein consumption is adequate carbohydrate, which aids in glycogen resynthesis (input of energy). Taken within the first 30 minutes post-exercise, research has shown that this protein/carbohydrate mixture will aid in the rebuilding and repairing process, as the carbohydrate replenishes depleted energy sources.
It is also essential to consume protein at least 30 minutes post-workout to prevent muscle breakdown. Delaying protein consumption post-workout, sometimes by two hours, may have a negative effect on muscle hypertrophy, meaning you are more likely to delay muscle growth, as opposed to repairing and rebuilding it.
When in doubt, my advice is to consult with a licensed dietitian and /or your physician to achieve appropriate daily protein intake in conjunction with a sensible eating plan relative to your activity level, age, and overall health profile.