Protein & Your Body

How your body uses protein to build lean muscle.

Been pumping iron for years? Athlete in training? Or maybe you just want to lose some excess body weight!

If you’re on this website then you already know that protein intake is essential for reaching your goal. Protein and the amino acids they contain are often referred to as the building blocks of life, and for good reason. But what really happens when you toss back a protein shake after your workout?

HOW YOUR BODY PROCESSES PROTEIN

When you consume protein its digested in the stomach where acid and enzymes break it down into amino acids. These amino acid molecules are transported into the bloodstream by special cells that line the walls of your small intestine. From your bloodstream they are transported to every part of your body for use.

While your body can create most of the amino acids required for your body, there are 9 it cannot. These 9 amino acids are often referred to as the “Essential Amino Acids” and these must be consumed in order for the human body to remain healthy.

Read more about the 9 Essential Amino Acids

THE 9 ESSENTIAL AMINO ACIDS

The following 9 essential amino acids are critical for muscle development, muscle energy synthesis, the circulatory and nervous system. These amino acids are essential for healthy muscle development, maintenance, performance and endurance.

Leucine

Leucine stimulates muscle growth and moderates insulin in the body.

Isoleucine

Isoleucine helps produce haemoglobin which carries iron in the blood.

Lysine

Lysine is used for mineral absorption, muscle repair and growth in the body.

Methionine

Methionine is used for muscle growth and the production of creatine.

Phenylalanine

Phenylalanine is used to make epinephrine, norepinephrine and l-dopa.

Threonine

Threonine is used to create collagen, elastin and muscle.

Tryptophan

This amino acid is used to make the neurotransmitter serotonin.

Valine

Valine helps in the supply glucose to muscles for use as energy.

Histidine

Histidine helps in the production of healthy blood cells and histamine.

PROTEIN ABSORPTION: HOW MUCH CAN THE BODY USE?

Your small intestine only has so many transporter cells and this limits the volume of amino acids your body can absorb each hour. Protein absorption varies dependant on the source and type of protein.

Maximum Protein Absorption Rates

While there is much research on the topic, the results on absorption rates are somewhat inexact due to the difficulty in testing this process. The following table should be used as a rough guide.

Note: The digestive process takes approximately 2 to 3 hours. So as a rule of thumb, your body will not use more that 3 times the absorption rate over a 3 hour period. So when taking a whey isolate supplement, you would not require more than 30grams per 3 hour period.

ABSORPTION (Grams Per Hour)

HOW MUCH PROTEIN DO WE NEED?

The recommended daily allowance of protein is an inexact science, as your own personal goals and athletic activities contribute to your protein requirements. Figures provided in this section are based on maintenance of current muscle mass. Where additional exercise and muscle building is occurring there is a higher requirement for protein intake.

As a general rule of thumb the following table outlines the calculations for the average person. However these figured do not take into account increased physical activity that an athlete or body builder requires. Therefor the following table should be used as a guide to the absolute minimum daily allowance.

Protein requirements are higher for those performing more rigorous exercise or athletic training. Athletes require higher levels of protein due to increased muscle damage repair as well as support for greater muscle growth, muscle endurance and energy synthesis for muscle cells.

Protein per poundProtein per kg
4 – 13 years0.43g0.95g
14 – 18 years0.39g0.83g
19+ years0.36g0.80g

WHAT HAPPENS WHEN EXCESSIVE PROTEIN IS CONSUMED?

While the more active of us do need more protein than others, there is still a limit to how much can be used by the body.

When you consume too much protein, ammonia builds up as a by-product in the body which is lost with sweat. If your sweat smells of ammonia, its likely that you’re consuming too much protein. Too much protein can also cause nausea when your body slows your digestive process to prevent toxic levels of ammonia building up.

DOES THE SOURCE OF MY PROTEIN REALLY MATTER?

There is no doubt about it, source counts! There are many reasons why the source of your protein matters and here are just some of the main reasons.

1
Not all sources of protein contain all the nine essential amino acids. This is particularly the case if you want to use plant based proteins where you need to ensure you are using either soy protein or a blend ensuring you receive all the essential amino acids.
2
Not all protein sources in high volumes are a healthy choice. Consider red meat which can also be high in saturated fats. This is why lean proteins are important and your selection of a healthy protein source essential.
3
Consider how protein supplements are derived. The way livestock are raised and fed effects the balance of amino acids and the quality of the suppliment product. This is also reflected in plant based products. We would always recommend grass fed and organically grown protein.

WHOLE FOOD PROTEIN Vs PROTEIN SUPPLEMENTS

Of course its important to have a good high protein diet from whole foods and we would recommend whole foods as a preferred source for normal intake of protein. However if you are a training athlete or looking to reduce your fat intake then protein supplements can be an effective way to boost your protein intake while succeeding with your goals.

Protein supplements are big business and you only need to check out your local health food store or supermarket to see the vast range of products on offer. These are supplements however, and should only be used to supplement your intake of protein to meet your requirements.