In nutrition, an essential nutrient is one that someone needs to survive, and protein is indeed an essential nutrient. Protein is composed of amino acids which are the building blocks that combine to form proteins. Some are referred to as essential amino acids which the body cannot produce itself, and others are referred to as non-essential amino acids which the body can produce itself. We want to prioritise high-quality protein sources that predominantly contain the essential amino acids to fulfill our bodies' protein requirements.
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Protein participates in pretty much every single process in a cell in every single cell in the body, whether to act as an enzyme that initiates and speeds up chemical reactions, to provide a source of energy, or, to repair muscle tissue after any kind of physical stress like exercise. While we understand the importance of protein in the diet, how much protein do we actually need?
Firstly, protein requirements are constructed based on the body's needs, which can depend on the life stage of an individual. Apart from the first few months of life, the body's protein requirements for children, adolescents and adults is set to maintain protein balance, which is to consume enough protein to replenish the protein stores that are lost through chemical reactions in the body, or, used for energy.
How much protein should I need daily?
The recommended daily allowance for protein is set at 0.8g per kg of body weight for adults. This equates to approximately 46g a day for a 57kg woman and 56g a day for a 70kg man. So, it's important to make sure you are at least hitting these protein targets throughout the day. However, there does not seem to be any evidence to suggest moderately more than this would be detrimental, and there has yet to be an established Tolerable Upper Intake Level (UL) for protein, but it is strongly advised to refrain from consuming any more than 200g of protein a day.
What if I train?
If you are someone who participates in endurance exercise or weight training then your protein requirements will likely be higher than normal, as you're placing more physical stress on your muscles, causing greater damage, and a greater need for recovery and repair. Therefore, it is important to provide a sufficient supply of amino acids to repair and build new muscle. With this in mind, The Sports Nutrition Consensus Statement recommends endurance athletes consume 1.2-1.4g of protein per kg of body weight to cope with the extra demands on the muscle (1), and the American College of Sports Medicine recommends between 1.2-1.7g of protein per kg of body weight (2).
What are the best sources of protein?
The degree to which a protein food source contains all the essential amino acids ultimately determines the protein quality of the food. There are other important requirements too, such as the ability for the protein to be easily digested and accessible to the body is able to be suitable for utilization.
Some of the best protein sources are the ones that contain all the key essential amino acids, these include:
Lean meats such as chicken and turkey
Eggs
Nuts
Soybeans
Fish
Legumes and beans
Vegetarian and vegan considerations
If you are vegetarian or vegan then it's important to make sure you're consuming high-quality meat-free protein sources, such as tofu, tempeh, and Quorn. Alternatively, combining non-complete protein sources which do not contain the full essential amino acid profile, such as grains and legumes, can help form complete protein sources (that contain all the essential amino acids when combined) which is a nice method to consume adequate protein. As the ability for the body to absorb the protein from non-meat sources may not be as efficient, it's always a good idea to consume slightly more protein from non-meat sources to account for this. This will help ensure your body gets sufficient protein to perform optimally!
Joe is an associate nutritionist and brings over 7 years of experience in appetite regulation, weight loss, and personalised nutrition. He is a registered associate nutritionist with the AfN & also works as a health coach looking at lifestyle factors that influence eating behaviours. If you'd like to know more, get your free nutrition assessment to get the best nutritional advice for you.