What is Protein?
Protein is incredibly important, and without it, our body composition and health greatly suffer as a result.
Proteins are essential nutrients 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 synthesize its own, meaning we must obtain these from animal and plant sources.
The other 11 aminos can be synthesized by the body, making them non-essential.
When considering a protein source, one of the most popular methods is to classify the food by its biological value (BV). The biological value of a protein is based on its quantity of the essential amino acids. 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.
The Role of Protein
When we do consume sufficient amounts of high-quality and complete proteins, it has a whole host of benefits.
Proteins provide building materials – amino acids – for growth and repair of body tissues
Proteins form vital parts of most body structures, such as skin, nails, hair, membranes, muscles, teeth, bones, organs, ligaments, and tendons
Proteins facilitate numerous chemical reactions in the body; all enzymes are proteins
Some proteins act as chemical messengers, regulating body processes; not all hormones are proteins
Proteins assist the body in maintaining its resistance to disease by acting against foreign disease-causing substances
Proteins help regulate the quantity of fluids in body compartments
Proteins act as buffers, to maintain the normal acid and base concentrations in body fluids
Proteins move the required nutrients and other substances into and out of cells and around the body
Protein can be used to provide calories (4 calories per gram) to help meet the body’s energy needs
Protein is the most effective food macronutrient providing a satiating effect meaning foods with increased protein contents can help to modulate food intake, promoting body weight loss and body weight maintenance thereafter
How much Protein do we need?
The debate still continues on how much protein we need daily, but there appears to be a general agreement that active individuals need a higher intake than sedentary people.
Average Intake: For a healthy person of a healthy weight who is mainly sedentary and is not seeking changes in body composition – then an intake of 0.8 grams of protein per kg of body weight is sufficient.
When Losing Body Fat: Having a higher protein intake during a calorie deficit is also important, as it is very anabolic, meaning we are more likely to preserve lean body tissue in the process. An intake of 1.6g to 2.2g grams of protein per kg of body weight is recommended.
When Building Muscle: The studies that look at muscle mass and protein intake tend to vary quite a lot. A balanced approach would be most beneficial, so around 2g to 2.4g per kg body weight is highly effective.
Elderly: The research shows a daily intake of 1.2g to 2g per kg bodyweight.
Finally, those recovering from injuries may also benefit from a higher protein diet.
Here's what you NEED to know ...
There is no link to protein causing an increased risk of coronary heart disease
There is no link to protein causing liver or kidney damage in healthy subjects
Recent studies show a positive relationship between protein intake and bone health
Animal Protein Sources
Plant and Dairy Protein Sources
Summary
Protein is needed for growth and repair of body tissues and is especially important for healthy muscles and bones, particularly for children.
Good food sources of protein are meat, fish, dairy products, eggs, nuts and soya, beans, peas and lentils. Smaller amounts are also found in grains and cereals.
It is important for health to include a range of protein-containing foods and we are recommended to eat more plant-derived protein foods.
People who do some physical activity, like going for a run or to an exercise class are unlikely to need any extra protein. For people exercising at a high level, having some protein soon after a training session can help muscles rebuild.