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Stop Focusing on Protein
A Primer on Amino Acids & Leucine
The importance of protein has become common knowledge: from the Greek word “first”, it is the building block of all cells in our body.
However, protein is only a delivery mechanism, and it’s the wrong thing to focus on.
Amino acids are the building blocks of all proteins. Amino acids in specific combinations and dosages have profound effects on our psychology, physiology, and physical body. This is where the disconnect lies.
There are 9 amino acids considered “essential” because our bodies cannot synthesize them and they must be obtained from diet, but they are mandatory for health and disease prevention. (1)
More than 9 amino acids are essential under certain conditions. For example, under conditions of stress and illness, glutamine may become essential because it’s a critical substrate for the immune system. (1)
It’s much simpler to focus on protein rather than the 20 amino acids, but it is dangerously misleading and brings some to the conclusion that all protein is equal.
For example, L-Leucine is the trigger for muscle protein synthesis, and a threshold of L-Leucine must be met in order to stimulate muscle protein synthesis. No matter how high your protein intake is in a meal, if you do not meet the Leucine threshold, you do not stimulate muscle protein synthesis. (3)
That is a problem for athletes who want to maximize recovery and adaptations to training, or maximize fat loss, but it’s also a problem for anyone interested in health, since muscle is critical as we age. Muscle and strength are associated with all causes of mortality.
In order to optimize amino acid intake, we focus on this critical amino acid with the “Leucine Threshold” Protocol.
Unless you’re already doing it, I’m unconvinced any other single factor will produce more rapid and dramatic changes across all domains:
Immunity, energy, cognition
Recovery - from training, illness, surgery, or injury
And most important of all: muscle growth, strength gains, & fat loss
The Leucine Threshold Protocol
What is the Leucine Threshold protocol?
Consume 40g of Quality Protein
Containing at least 3g of L-Leucine
3-4 times daily
4-5 hours apart
Why 3g of L-leucine?
We focus on leucine for several reasons:
High leucine foods are an excellent measure of general amino acid quality. When we meet the leucine threshold, we also tend to fulfill all of the essential amino acids. This is not always the case, but it tends to be true. Leucine is the Occam’s razor of amino acids, so to speak.
A high leucine meal tends to contain many other essential or beneficial nutrients. For example, red meat is an excellent source of leucine, and contains many vitamins and minerals such as B12, zinc, and iron, as well as other beneficial nutrients such as creatine, tyrosine, and carnosine.
A high leucine meal is satiating.
The reason we use 3 grams is because, while it likely takes slightly less to maximize muscle protein synthesis if you’re under 40, the leucine threshold also may increase when foods are combined.
This is because muscle protein synthesis is stimulated not only by meeting the leucine threshold, but by the rate of leucine absorption, and the rate is slowed when combined with other nutrients like fats and fibers.
I’m not sure I can stress enough how beneficial it is to stimulate muscle protein synthesis. We stimulate muscle growth without training, and this has extraordinary effects on fat loss, even for people who do not train. (More on this in the next section)
Furthermore, I’d rather maximize the satiating, energizing, thermogenic effects of leucine, and ensure a quality source of protein is consumed.
Why 4-5 hours apart?
This tends to be the sweet spot to ensure maximal muscle protein synthesis by avoiding anabolic resistance and preventing muscle protein breakdown.
We store amino acids in muscle tissue. Around 4 hours after a meal that stimulates muscle protein synthesis (MPS), MPS begins to drop again and amino acids are catabolized from muscle tissue. We do not want to lose muscle tissue, so we stimulate MPS and consume amino acids again so breakdown is not needed.
Why 3-4 times daily?
This tends to be the amount of meals necessary to keep MPS high and meet optimal protein requirements for trainees, 1g per pound. More may be necessary for intense training or maximal muscle growth, especially in more experienced trainees, to maximize satiety, or to ensure minimal muscle loss during weight loss. (6)
7-8am, 11am-12pm, 3-4pm, 6-7pm. This also tends to be a good circadian rhythm practice. Each feeding does not need to be a full course solid meal. During training, for example, we can use a protein powder supplement such as pure amino acids, whey, beef, egg, or some other type of quality protein that meets the leucine threshold.
Research: High Protein vs Low Protein
Even if you don’t train, you will receive results from this protocol.
Donald Layman is a foremost authority on leucine and amino acids pertaining to muscle and health. One study from his lab titled “Dietary Protein and Exercise Have Additive Effects on Body Composition during Weight Loss in Adult Women” compared 2 diets, low protein high carb (CHO) vs high protein low carb (PRO), and 2 groups for each diet, one with exercise and one without exercise. (7)
Energy/calorie intake was controlled for each diet, and the PRO diet “emphasized the use of high-quality proteins including meats, dairy, and eggs.”
In summary, from the abstract: “ Subjects in the PRO and PRO + EX groups lost more total weight and fat mass and tended to lose less lean mass (P = 0.10) than the CHO and CHO + EX groups. Exercise increased loss of body fat and preserved lean mass. The combined effects of diet and exercise were additive for improving body composition.”
To highlight: subjects on the high protein diet lost more weight and fat mass than those on the low protein diet, even when the low protein diet included 7 exercise sessions per week.
When we combine exercise and a high protein diet, the study found 96% of the weight lost was fat.
In the coming weeks, we’ll dive deep into optimal amino acid intake for health, body composition, and performance (both cognitive and athletic).
I invite you to join me and support independent research and education by subscribing for free to the Honor Strength Newsletter.
For now, I implore you to experiment with the leucine threshold strategy outlined above. I have seen rapid, radical results from this protocol many times. It has been used with every physique transformation I’ve produced.
Yours in Strength,
Daniel J. Furtado, CPT, LMT, Owner of Honor Strength
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Many of the concepts written in this article were pioneered by the writings and research of Donald Layman and his students, from whom I have also learned a great deal, Layne Norton and Gabrielle Lyon.