Ingredient Science

Amino Acids, Protein and Muscle Strength: What to Know

February 8, 2024 by Enzymedica Team
Amino Acids, Protein and Muscle Strength: What to Know

While you often hear about protein being important for athletes and other active people, everyone needs to consume adequate amounts of this macronutrient. Foods like meat, fish, dairy, soy and legumes provide protein.

Muscle strength is also important for all humans of all ages, whether or not you pump iron, run marathons or practice yoga. Amino acids are the building blocks of protein, and they are responsible for carrying out crucial tasks in the body.

In this guide, you’ll learn about protein and amino acids, the roles they play in the body and what you need to know about muscle strength. Plus, if you’re intermittent fasting (or thinking about it), you’ll want to read to the end.

What are Amino Acids and Why are Some Essential?

The foods we eat provide calories (units of energy) and a combination of macronutrients (carbohydrates, fiber, protein and fat) and micronutrients (including vitamins and minerals). Throughout the digestive process, those macros get broken into their building blocks. In the case of proteins, those building blocks are amino acids. Think of protein as a friendship bracelet at a Taylor Swift concert, with each bead as an amino acid.

There are 20 total amino acids, and the ones that cannot be synthesized in the body are called essential. The rest are divided into two groups. Non-essential amino acids can be made from essential amino acids or during the normal breakdown of proteins. Conditional amino acids are only needed at certain times (when the body experiences systemic stress, an injury or an immune threat).

Three essential amino acids are considered BCAAs (branched-chain amino acids): leucine, isoleucine and valine. “Branched-chain” refers to their chemical structure. We will discuss the benefits of all amino acids later on.

What Do Protein and Amino Acids Do?

Proteins are chains of amino acids linked together. Throughout the digestive process, those chains are broken down into the most basic structures. Foods like eggs, milk, yogurt, meat, fish, soy (tofu, tempeh, etc.), beans, quinoa, legumes, nuts and seeds all provide protein and some combination of amino acids. Whole grains and vegetables also provide some protein.

Proteins (and amino acids) are responsible for many roles:

  • Support tissue growth and maintenance (including muscle tissue)
  • Carry messages between cells and tissues
  • Help store and transport nutrients
  • Form the structure of cells and tissues
  • Cause chemical reactions (that’s the work of enzymes)
  • Help maintain fluid balance in the body
  • Supports immune health (the body’s natural antibodies are actually proteins)


Consuming adequate amounts of protein is especially important for active individuals, those who are intermittent fasting or restricting calories and older adults. Muscle mass begins to decline around age 30 (a natural process that speeds up even more after age 60), with decreases of 3% to 8% per decade.

How Much Protein Do People Need?

While fiber is a nutrient of concern for 95% of Americans (who don’t eat enough of this beneficial nutrient), most people consume adequate amounts of protein to cover their basic daily needs. However, there are different recommendations depending on age, sex, activity level and goals.   

Most adults need a bare minimum of 50 grams of protein daily, according to the 2015-2020 Dietary Guidelines for Americans. (Your nutritional needs changes slightly after age 50.) Adults are advised to consume 0.8 grams of protein per kilogram of body weight daily. One kilogram equals 2.2 pounds, so a 175-pound person would aim for a little more than 63 grams.

If you are focused on healthy weight management, research supports getting about 30% of your daily calories from protein. On a 1,800-calorie diet, that’s about 135 grams. (Protein provides 4 calories per gram.)

If you are focused on increasing endurance, protein intakes between 1.0 and 1.6 grams/kilogram of body weight are adequate, which is the position of the International Society of Sports Nutrition. That 175-pound person would aim for up to 127 grams daily. If your goal is hypertrophy, protein intake of 1.6 to 2.0 grams is appropriate for strength and power exercise regimens. (That’s up to 159 grams of protein daily for the 175-pound person.)

Those amounts help maintain healthy bone metabolism and kidney function. Amounts up to 2.0 grams per kilogram of body weight are safe, per the ISSN.

List of Essential Amino Acids

There’s a lot of debate about EAAs vs. BCAAs (which are also EAAs).  All EAAs are essential to muscle protein synthesis, but EAAs are a more complete source of the building blocks of protein. They stimulate more muscle protein synthesis than BCAAs.

Here are the nine amino acids that are considered “essential,” in alphabetical order. Note: “L” is part of their official chemical name, but it gets dropped from the name in everyday conversation and writing.

Histidine: used to make the neurotransmitter histamine to support immune response, digestion, circadian rhythm and sexual function, along with maintaining the myelin sheath that protects your nerve cells).

Isoleucine: A BCAA that supports muscle metabolism, immune function, energy regulation and production of hemoglobin (the protein in red blood cells that transports oxygen to cells and tissues). It is concentrated in muscle tissue.

Leucine: Another BCAA. Supports protein synthesis and muscle repair, helps regulate blood sugar levels and wound healing.

Lysine: Supports and promotes protein synthesis, energy production, immune function, calcium absorption, hormone production, formation of collagen and enzyme production.

Methionine: Supports healthy metabolism and detoxification, tissue growth and absorption of zinc and selenium.

Phenylalanine: Used to form dopamine, tyrosine, epinephrine and norepinephrine (all neurotransmitters), supports protein and enzyme structure and function and production of other amino acids.

Threonine: the foundation of collagen and elastin, two structural proteins that are important parts of connective tissues and skin. Also supports immune function and fat metabolism.

Tryptophan: A precursor to serotonin, a neurotransmitter that regulates appetite, mood and sleep.

Valine: This is another BCAA, which helps promote muscle growth and regeneration and energy production.

Why Did We Include Amino Acids in Fasting Today?

When you fast, instead of turning to food for fuel, your body taps into your energy stores. While the ideal sources are glycogen (carbs stored in muscles and the liver) and fat, the body can also use lean muscle mass as fuel. If you haven’t eaten in hours, your glycogen stores naturally are lower. Adequate protein intake is required during intermittent fasting to retain and build lean muscle mass.

The nine essential amino acids support muscle strength and body composition, and promote muscle protein synthesis.* During a fast, your body will have access to a supply of essential amino acids.*

Formulated to not break your fast – so you can focus on your goals – Fasting Today® from Enzymedica is also ideal for ketogenic and other diets.* Fasting Today supports hydration, reduces hunger and promotes muscle health.*  

Intermittent fasting offers proven benefits for the body and brain, including support for healthy weight management, healthy energy levels, brain health and healthy aging.* It involves extending the natural periods of time humans spend not eating, to promote various benefits.* But fasting can be challenging on your body.* With a delicious tropical pineapple flavor, Enzymedica’s Fasting Today® is formulated with ingredients to help make your fasting successful.  

With three essentials in one convenient product, it includes electrolytes, baobab fiber and the nine essential amino acids. Simply shake a scoop with 12 ounces of water, then drink up and carry on with your fast.

Fasting and Exercise: What to Know

Life doesn’t get put on hold when you are fasting, and that includes exercise while fasting. What is the best timing for exercise during a fast?

Time your workout toward the end of your fast, according to Dr. Jason Fung, author of The Complete Guide to Fasting. Then, once your workout is over, break your fast and refuel your body. (Always talk to a health-care or fitness professional about your unique needs and goals.)

Keep in mind that exercise actually causes a little damage. That’s how you get stronger: Working out cause microtears in muscle tissue, which are repaired and grow bigger. While that sounds intense, it’s completely normal and healthy.

Once you’ve worked out, it will be time to break your fast. While the 30-minute “anabolic window” (the once-hyped short time period after a workout where your muscles are most receptive to protein) has been largely debunked, you will want to refuel your body to ensure your body gets the nutrients it needs to support healthy recovery.