How much protein do we need to lose weight and gain muscle, as well as achieving optimal health?
The three main macronutrients are protein, fats and carbohydrates, with ‘macro’ simply meaning large, and these are the nutrients that are most common in our diet. On the flipside, micronutrients are those that are in much lower quantities in our diet.
This article will look at protein and provide you with an understanding of the macronutrient and its importance in human health.
What Is Protein?
Protein is incredibly important, and without it our body composition and health greatly suffer as a result.
Proteins are an essential nutrient and can be broken down into 20 building blocks known as amino acids. Out of these 20 amino acids, 9 are considered to be essential as the body cannot make them itself. This means that we must obtain these from the diet, through a variety of animal and plantbased sources. And yes, it is definitely possible to source all of these from plantbased sources. The other 11 aminos can be synthesized by the body, making them non-essential.
The table below shows how protein can be broken down into its essential and non-essential amino acids.
ESSENTIAL AMINO ACIDS | NON-ESSENTIAL AMINO ACIDS |
|---|---|
Histidine | Alanine |
Isoleucine* | Arginine** |
Leucine* | Asparagine |
Lysine | Aspartic Acid |
Methionine | Cysteine** |
Phenylalanine | Glutamic Acid |
Theronine | Glutamine** |
Typtophan | Glycine** |
Valine* | Proline** |
Cell | Selenocysteine** |
Cell | Serine |
Cell | Taurine** |
*Branched-chain amino acids | Tyrosine** |
Within the 9 essential amino acids, there are 3 branched-chain amino acids (BCAA’s): leucine, isoleucine and valine. These are again different to the others as they do not require metabolizing by the liver, and are therefore taken up directly by skeletal muscle. Also, these 3 aminos are the most important for the manufacture, maintenance and repair of muscle tissue as they are responsible for the “flicking on” of the muscle building process, known as protein synthesis.
Of the three, leucine has shown to be the most effective amino at stimulating protein synthesis (the process of building muscle protein and therefore growth), yet the three work better together to provide a host of benefits and even boost energy during workouts. (1) (2)
Studies show that BCAA supplementation alone can blunt the catabolic hormone cortisol and decrease delayed-onset muscle soreness. (3)
Below is a table that shows the protein quantity in many of the common foods we eat:
ANIMAL PROTEIN FOODS | 1G EDIBLE PROTEIN PER 100GIN WEIGHT | PLANT & DAIRY | 1G EDIBLE PROTEIN PER 100GIN WEIGHT |
|---|---|---|---|
Beef Topround Lean Cooked Trout | 36.12g 26.63g | Pumpkin Seeds Walnuts | 32.97g 15.03g |
What Is The Best Protein For Weight Loss And Muscle Gain?
When considering a protein source or determining its amino acid profile values, one of the most popular methods is to classify the food by its biological value (BV).
What is biological value?
The biological value of a protein is the measure of protein that is used from foods we eat. This uses the quantity of the essential amino acids as well as the digestibility of the protein to rank different food sources. So, a food with a high BV (also known as a complete protein) contains all 9 essential aminos. This is commonly seen in animal and dairy products.
A food with low to medium BV does not contain all of the essential amino acids. This is common in plant-based protein sources, and it is only when these low BV foods are combined that you can create a higher quality BV in meals. This alone is a key reason as to why animal proteins (meat & dairy) are so important in our diets.
Below is a table showing food sources that provide a complete and incomplete amino acid profile:
Biologically Complete Proteins | Incomplete Proteins |
|---|---|
Eggs | Cereals |
Milk | Legumes |
Beef | Grains |
Poultry | Cell |
Soybean | Cell |
Quinoa | Cell |
Fish and seafood | Cell |
What Are The Benefits Of Eating More Protein?
In addition to asking how much protein do we need to lose weight and gain muscle, it is worth noting that protein consumption has wide ranging benefits. When we do consume sufficient amounts of high quality and complete proteins, it has a whole host of benefits.
THE FUNCTIONS OF PROTEINS
Growth and Maintenance:
- Body structures. Proteins form vital parts of most body structures, such as skin, nails, hair, membranes, muscles, teeth, bones, organs, ligaments and tendons.
Regulatory Roles:
- Enzymes. Proteins facilitate numerous chemical reactions in the body; all enzymes are proteins.
- Hormones. Some proteins act as chemical messengers, regulating body processes; not all hormones are proteins.
- Antibodies. Proteins assist the body in maintaining its resistance to disease by acting against foreign disease-causing substances.
- Fluid balance. Proteins help regulate the quantity of fluids in body compartments.
- Acid-base balance. Proteins act as buffers, to maintain the normal acid and base concentrations in body fluids.
- Transportation. Proteins move the required nutrients and other substances into and out of cells and around the body.
Energy Production:
- Energy. Protein can be used to provide calories (4 calories per gram) to help meet the body’s energy needs.
Protein Metabolism In Your Body
There are around 50,000 different protein-containing compounds in the body, and 65% of them are found in skeletal muscle.
This means we will have a high level of amino acids in our blood and body fluids. This process only occurs after regular protein intake. Before amino acids can enter the blood stream, protein must be digested in the stomach. This occurs when hydrochloric acid creates an active enzyme known as ‘pepsin’.
Structurally, proteins consist of various combinations of amino acids linked together by peptide bonds. Pepsin is the enzyme responsible for breaking down the peptide bonds to form smaller peptides and free-form amino acids.
From here, the proteins are passed onto the small intestines, and are at this point finally digested to absorbable amino acids.
From here, the amino acids can enter the amino acid pool and will be used in a matter of two ways by the body:
- Protein synthesis will create new proteins for the body in terms of body tissue (muscle, liver, kidneys etc), hormones, enzymes and all the other previously mentioned functions of proteins.
- Excreted by urine as urea (nitrogen containing organic compound), or converted to fat and/or cholesterol (This will occur only if there is an excess protein balance and/or energy intake is higher than what is needed).
The table below summarizes this metabolic process:
How Much Protein Should I Eat For Losing Weight And Building Muscle?
When deciding how much protein we need in order to achieve a weight loss or muscle building goal, we must resort to the research that can help us make the right decisions, yet it too seems to vary from source to source.
The average protein intake
For a healthy person of a healthy weight who is mainly sedentary and not seeking changes in body composition – then an intake of 0.4 – 0.6 grams of protein per pound body weight is sufficient.
When losing body fat
Protein has a high thermic effect, which means it requires more energy just to break it down, assimilate and digest than carbohydrates and fat. It also takes longer to digest, and has been shown to reduce appetite compared to carbohydrates and fat. (5) (6)
We also need protein to build muscle, which is very important when following a fat-loss diet. The more muscle you have, the more you’ll burn daily, the less stair-climber sessions you’ll need to do!
Having a high protein intake during a Calorie deficit is also important, as it is an anabolic nutrient, meaning we are more likely to preserve lean body tissue, which can sometimes be broken down when dieting. (9)
When building muscle
The key to building muscle is a positive protein balance. This is achieved when protein synthesis exceeds protein breakdown. A higher protein diet will upregulate protein synthesis (provided you have evenly spaced meals), which creates a net positive protein balance, resulting in that anabolic (building) environment. (10)
The studies that look at muscle mass and protein intake tend to vary from 0.8-1.0+ gram per pound bodyweight, so it’s safe to say a balanced approach would be most beneficial, so around 1g per pound bodyweight is highly effective. (11) (12)
Active and elderly
Body composition goals aside, you may find some clients are highly active, through their jobs or activities (such as endurance training).
The research shows a daily intake of 0.5-0.65 grams per pound bodyweight for these types of people. (13)
Elderly people can also benefit from more protein to help prevent aging diseases such as osteoporosis and sarcopenia (reduced muscle mass).
The research shows a daily intake of 0.45-0.6 gram per pound bodyweight. (14) Finally, those recovering from injuries may also benefit from a higher protein diet.
Is Protein Type And Timing Important?
We have already discussed that we assess the quality of our protein sources via the BV, therefore the type of protein we ingest will improve the results we see.
We also know that animal protein sources are more effective than most plant-based sources, at stimulating muscle protein synthesis due to their digestibility (low-fiber) and amino acid profile.
Also, proteins that contain high levels of BCAA’s, particularly leucine, will produce greater protein synthesis, improve insulin signaling and spare glucose in muscle cells.
Is Eating Too Much Protein Dangerous?
Many people will try and tell us that a high protein diet is bad for us, and that it is linked to cardiovascular disease, dehydration, calcium loss and damaged liver and kidney function.
The question that must be asked is – show us the accurate research.
The small amount of research that may support these dangers appears - just like many things in the nutritional world - to have been greatly exaggerated.
Here’s what you need to know:
- There is no link to protein causing increased risk of coronary heart disease (15)
- There is no link to protein causing liver or kidney damage in healthy subjects (15),
- Recent studies show a positive relationship between protein intake and bone health. (16)
Understand The Importance Protein
You should now understand the importance of protein in the human diet, how it is metabolized, how to measure quality, assess daily intake for various populations, compare protein types and de bunk some of the myths that surround it.
I hope this helps you make some informed decisions about how much protein you need to eat for your goals. If you know someone who would benefit from this article, please send them here.
References and further reading
What Is Protein And How Much Do We Need?
1. http://www.ncbi.nlm.nih.gov/pubmed/18056791
2. http://www.ncbi.nlm.nih.gov/pubmed/21775557
3. http://www.ncbi.nlm.nih.gov/pubmed/24195702
4. http://www.nal.usda.gov/fnic/DRI/DRI_Energy/energy_full_report.pdf
5. http://www.ncbi.nlm.nih.gov/pubmed/18448177
6. http://www.ncbi.nlm.nih.gov/pubmed/8862477
7. http://www.ncbi.nlm.nih.gov/pubmed/11838888
8. http://www.ncbi.nlm.nih.gov/pubmed/20565999
9. http://ajcn.nutrition.org/content/early/2012/01/17/ajcn.111.026328
10. http://www.jissn.com/content/9/1/42/abstract
11. http://www.ncbi.nlm.nih.gov/pubmed/22150425
12. http://www.ncbi.nlm.nih.gov/pubmed/19927027/
13. http://www.ncbi.nlm.nih.gov/pubmed/17213878
14. http://www.ncbi.nlm.nih.gov/pubmed/16886097
15. http://www.jissn.com/content/1/1/45
16. http://www.ncbi.nlm.nih.gov/pubmed/21102327
17. https://3.bp.blogspot.com/_tO5ykvLozeA/TTUyqvHrM9I/AAAAAAAAAB0/-oFTVTTnLA8/s1600/Protein+functions.jpg
18. http://mikestriathlon.com/nutrition-the-role-of-protein-in-sports-performance/
19. http://www.lifetime-weightloss.com/blog/2012/8/11/performance-enhancement-part-2
-essentials-of-repair-and-reco.html
20. http://kpbodyreconstruction.com/personal-diet-nutrition/high-protein-foods-list/