Last week we talked about everything to do with carbohydrates. This week we will be talking about another important macronutrient – protein.
This guide covers everything you need to know about protein, including:
What is Protein?
Protein is a macronutrient, meaning your body needs to intake large amounts of it through food/diet.
Like carbohydrates, protein can be a source of energy. Protein contains 4 kilocalories (aka calories) of energy per gram.
However, protein’s primary purpose is not to be burned as fuel for energy. Rather, protein is crucial for your body to carry out various functions and work properly.
You’ve probably heard how important protein is for things like muscle building and repair. However, protein is also extremely important for all other aspects of the body’s functioning, such as metabolism, circulation, growth, development, immune defense, transport throughout the body, signalling throughout the body, cell cycling, building cells and proteins in the body, and more.
Protein is made up of, and gets broken down into, molecules called amino acids, which are the building blocks for all proteins in the body.
Types of amino acids
There are a total of 20 different amino acids. Each have their own name, structure, and function, and all are important.
9 of the amino acids are known as essential amino acids because they cannot be produced in the body and must be obtained through diet.
The other 11 amino acids are nonessential amino acids because they can be produced by the body if needed/if not obtained through diet.
Why is Protein Important?
Without protein, your body would not function properly at all.
Proteins in the body are crucial for carrying out pretty much every bodily function – carrying oxygen, fighting infection, signalling and communicating within the body, transporting substances within the body, digesting, providing satiation, building and repairing tissue, building hormones, etc.
Amino acids are the building blocks for important protein molecules including enzymes, hormones, antibodies, neurotransmitters, and more – these are the molecules that are necessary to carry out the above listed functions.
It is important to get adequate dietary protein so that your body can break it down into amino acids which it then uses to build all the different proteins your body needs.
Protein is also the most satiating energy source, meaning it helps keep us full for longer than other energy sources such as carbohydrates. Dietary protein can help manage calorie intake and eating habits, balance blood sugar, increase metabolic rate, increase muscle mass, and reduce risk of glucose intolerance/insulin resistance.
How Much Protein Do You Need?
Exactly how much protein we should be consuming each day, is still up for debate. Unfortunately, there is no clear cut answer here.
Generally, about 10% of daily calories should come from protein (1).
The Recommended Dietary Allowance (RDA) for adults is 0.8g of protein per kg (or 0.36g of protein per pound) of body weight per day.
This works out to a 150-pound person needing at least 54g of protein each day.
To calculate the recommended daily protein intake for your weight, simply multiply your weight in pounds by 0.36.
However, this RDA number is just a baseline. Some experts believe that this should be the minimum amount of dietary protein your body needs to intake each day, but that most people can benefit from consuming more than this small amount. On the other hand, others believe that most diets provide too much protein. (1)
The answer remains unclear, and how much protein you need can vary between individuals.
Who should eat more protein?
Some individuals may benefit from more protein that the RDA of 0.8g/kg of body weight/day. These individuals include:
- Active individuals, athletes, individuals working to gain and/or maintain muscle mass
- Individuals recovering from injuries (2)
- Pregnant and breastfeeding women (3)
- Older individuals, especially those at risk of osteoporosis and sarcopenia (loss of muscle mass and strength due to aging) (4)
- Individuals trying to lose weight, manage eating habits, control hunger cues, reduce sugar/carbohydrate intake and manage blood sugar levels.
Can you eat too much protein?
Too much protein may have some harmful effects. High protein intake (from animal sources) has been linked to increased risk of developing kidney stones (5).
High consumption of protein-rich foods may also increase processed carb and saturated fat intake (depending on the food source) which may lead to increased risk of heart disease.
Unfortunately, there is no established tolerable upper limit (UL) for how much protein to eat; experts have not agreed on a set amount of what constitutes too much protein.
Types of Protein Sources
Protein can be obtained through both animal and plant foods.
These two types of food sources differ in the amino acids they provide.
Animal sources of protein provide all the essential amino acids, while plant sources of protein lack at least one essential amino acid, or do not contain sufficient amounts. This has implications for individuals following a plant-based diet.
Best Dietary Sources of Protein
In cases such as this, where the recommended daily protein intake is unclear and highly variable, it may be a good idea to consume a wide variety of protein sources. Natural, whole food sources are the most bioavailable sources of protein, and a balanced diet of nutrient dense foods will provide sufficient protein without having to dabble into supplements. Healthy protein-rich foods include:
- meat – red meat, poultry, pork
- seafood – fish, shellfish
- dairy – yogurt, cottage cheese
- legumes – beans, lentils, edamame, soy/tofu/tempeh
Protein is a macronutrient that is essential to a variety of important functions in the body such as tissue growth, development, and repair, immune system defence, and more. The best dietary sources of protein include animal products such as meat, seafood, eggs, and dairy, and plant foods such as legumes, grains, nuts, and seeds.
That’s it for this article on protein! Stay tuned for next week’s guide to our final macronutrient – fat!