What is protein?
Protein is one of the main nutrients your body needs in large amounts. These are called macronutrients, and they include protein, carbohydrates, and fats.
Protein is important because it helps your body:
- Build and grow muscle when combined with strength or resistance training.
- Maintain muscle mass and protect lean tissue as you age or during weight loss.
- Keep you feeling full for longer, which can help manage appetite and support healthy eating habits.
Different types of protein sources
Not all protein sources are the same.
When proteins are digested, they are broken into things called amino acids, which your body uses to build and repair tissue. There are 20 different amino acids in total. Your body can make some of them, but 9 of them, which are called essential amino acids, must come from the foods you eat.
Foods that contain all 9 essential amino acids are called complete proteins. Most animal-based foods, such as meat, fish, eggs, and dairy products, are complete protein sources. Many plant-based proteins, such as beans, lentils, nuts, and grains, may have lower amounts of some essential amino acids or may be missing one or two, so they are often called incomplete proteins. However, eating a variety of plant-based foods throughout the day can still provide all the amino acids your body needs.
General Protein Intake Recommendations
The recommended daily allowance of protein in Canada is 0.8 grams/kg/day for all individuals aged 18 and older. However, this value only applies to individuals participating in minimal physical activity looking to maintain muscle function.
Your actual protein needs vary depending on several factors including:
- Physical activity
- Age
- Diet type
For individuals participating in resistance training, daily intakes of 1.4 – 2.0 g/kg/day is the minimum recommended amount while more may be needed for people attempting to restrict caloric intake while minimizing muscle loss.
For elderly adults, research has shown that 1.2-2.0 g/kg/day or higher is sufficient for maintaining muscle function regardless of participation in physical activity. Increased protein intake in older adults is important because it can help prevent sarcopenia, which is a musculoskeletal disease that is characterized by progressive loss of muscle size and function and increased risk of falling.
Not all protein sources are exactly the same when it comes to how well the body can use them. As mentioned previously, people following a plant-based diet can still get all essential amino acids by eating a variety of plant foods. However one thing to take into consideration is that plant proteins are slightly less easily absorbed by the body. As a result, some research suggests that vegetarians may benefit from slightly higher protein intake around 1.0 g/kg of body weight instead of 0.8/kg. For vegetarian athletes who participate in resistance training, protein needs are higher to support muscle repair and growth. Research suggests an intake of approximately 1.6–2.2 g of protein per kilogram of body weight per day.
Dispelling myths – is too much protein bad for your kidneys?
A common concern is that eating too much protein can harm kidney health. However, research has shown that higher protein intake ~20-35 % of total daily calories is generally safe and consistent with healthy kidney function in people who do not have pre-existing kidney disease. It is important to note that this research does not apply to individuals with conditions such as Chronic Kidney Disease (CKD). People with CKD or other kidney related conditions should consult a healthcare professional to determine the appropriate level of protein intake for their individual needs.
General advice on how to increase protein intake
Increasing protein intake can be achieved through simple dietary changes. One helpful strategy is to include a source of protein at every meal. For example, breakfast options such as eggs, egg whites, or Greek yogurt can provide a strong start to the day. Choosing high-protein snacks is another easy way to increase daily intake. Snacks such as cheese, hard-boiled eggs, cottage cheese, Greek yogurt, or protein-enriched foods like protein chips can help boost protein consumption between meals. Another approach is to choose higher-protein versions of common foods. For instance, using protein-fortified milk instead of regular milk, selecting lentil or chickpea pasta instead of traditional pasta, or adding extra egg whites to whole eggs can increase the protein content of meals without drastically changing eating habits.
Summary
Protein is an essential nutrient that plays a key role in supporting muscle growth, tissue repair, and overall health. While the general recommendation for adults is 0.8 grams of protein per kilogram of body weight per day, individual needs can vary depending on factors such as physical activity level, age, and dietary choices.
People who regularly participate in resistance training may benefit from higher protein intakes of 1.4–2.0 grams per kilogram of body weight per day to support muscle repair and growth. Older adults are also encouraged to consume more protein, approximately 1.2–2.0 grams per kilogram per day, to help maintain muscle mass and reduce the risk of muscle loss associated with Sarcopenia.
Individuals following a plant-based diet may also benefit from slightly higher protein intake to account for differences in the digestibility of plant-based protein sources. Overall, adjusting protein intake based on individual needs can help support long-term health, strength, and physical function.