What Is Protein And How Much Do We Need?

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.

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 essential as the body cannot make them itself. This means that we must obtain these from the diet, through a variety of animal and plant-based sources. And yes, it is possible to source all of these from plant-based 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**
	Selenocysteine**
	Serine
	Taurine**
	Tyrosine**

*Branched-chain amino acids

**Conditionally essential amino acids

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 100G IN WEIGHT	PLANT & DAIRY PROTEIN FOODS	1G EDIBLE PROTEIN PER 100G IN WEIGHT
Beef Topround Lean	36.12g	Pumpkin Seeds	32.97g
Pork Bacon	35.73g	Peanut Butter	25.09g
Beef Brisket Lean	33.26g	Cheddar Cheese	24.90g
Beef Steak Lean	31.06g	Monterey Cheese	24.48g
Beef Top Sirloin Lean	30.55g	Colby Cheese	23.76g
Pork Top Loin	30.48g	Peanuts	23.68g
Bluefin Tuna	29.92g	Mozzarella Cheese	22.17g
Turkey Bacon	29.60g	Almonds	22.09g
Chicken Dark Meat	28.99g	Pistachio Nuts	21.35g
Oyster	28.81g	Flaxseeds	19.50g
Beef Tenderloin Lean	28.51g	Tofu	17.19g
Turkey White Meat	28.48g	Egg Yolk	16.89g
Beef Kidney	27.27g	Cashew Nuts	15.86g
Halibut	26.69g	Hazelnuts	15.31g

ANIMAL PROTEIN FOODS	1G EDIBLE PROTEIN PER 100G IN WEIGHT	PLANT & DAIRY PROTEIN FOODS	1G EDIBLE PROTEIN PER 100G IN WEIGHT
Cooked Trout	26.63g	Walnuts	15.03g
Veal Cooked	25.93g	Fried Egg	15.03g
Beef Liver	25.51g	Soybeans	13.63g
Cooked Salmon	25.56g	Whey	13.10g
Goose	25.16g	Cottage Cheese	12.93g
Caviar	24.60g	Ricotta Cheese	12.49g
Lamb Cooked	24.52g	Pecans	11.26g
Freshwater Bass	24.18g	Lentils	9.50g
Flounder	24.16g	Wheat Bread	9.02g
Beef T-bone	24.05g	Acorn Nuts	8.80g
Hamberger 80% Lean	24.04g	Lima Beans	7.80g
Duck	23.48g	Macadamia Nuts	7.79g
Turkey	23g	Mungo Beans	7.54g
Pork Chop	21.91g	Cranberries	5.54g
Turkey Gizzard	21.72g	Green Peas	5.36g
Turkey Heart	21.42g	Ointo beans	4.86g
Anchovy	20.35g	Kidney Beans	4.83g
Lobster	20.50g	Yogurt	3.47g
Shrimp Moist Heat	20.92g	Non-Fat Milk	3.37g
Turkey Liver	20.02g	Whole Milk	3.22g
Alaska King Crab	19.35g	White Rice	2.69g
Chicken White Meat	16.79g	Brown Rice	2.58g

Therefore, 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 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.

Timing & Type

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.

Dangers Of A High Protein Diet

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)

Summary

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.