All about Protein

Protein is one of the three main macronutrients in our diets (carbohydrates and fat are the other two) and is an essential nutrient that is a component of all cells, tissue, and organ in the human body. Protein found in the foods we eat is digested into amino acids which are then later used to repair proteins found in our body.

What does protein do?

The protein we eat in our food is used for a variety of functions in the body including:

  • Production of the building blocks for all tissues in the body including muscles, connective tissues, hair, skin, and nails
  • Production of important enzymes like lactase and hormones like insulin.
  • Production of transport proteins such as hemoglobin which carries oxygen around the body.
  • Production of antibodies which help protect your body from bacteria, viruses and other foreign invaders.

What foods contain protein?

The first food that many people think of when you say the word protein is meat however there are many other foods that also contain a significant amount of protein.

Foods that contain protein can be broken down into two different categories: incomplete proteins and complete proteins. Complete proteins contain all essential amino acids (building blocks) whereas incomplete proteins only contain certain essential amino acids. Generally, complete proteins come from animal products and incomplete proteins come from plant sources of protein. If you are a vegetarian, combining different “complimentary” incomplete proteins can help you to easily obtain all essential amino acids (ie. black beans and rice).

Vegetables and Fruits: contain very little protein and are generally not a good source of protein in our diet.

Grain products: such as whole grain barley, quinoa, oats and wheat contain a moderate amount of protein however grain products are incomplete proteins and need to be combined with complimentary sources of protein such as beans and legumes in order to provide all essential amino acids.

Milk and Alternatives: are great complete sources of protein to include in your diet.

  • Milk, yogurt, cheese, cottage cheese, kefir and soy milk contain all essential amino acids and other important nutrients such as calcium, vitamin D, magnesium, riboflavin and vitamin B12.
  • Note: Milk alternatives other than soy beverage such as almond milk, rice milk and coconut milk do not contain significant amounts of protein and often are not fortified with the same amount of calcium and vitamin D as cow’s milk. These are fine to use as alternatives however it is important to read the food label to ensure that the nutrient profile is similar to cow’s milk.

Meat and Alternatives: Both animal and plant sources of protein are found in this food group. Vegetarians/vegans are encouraged to include a variety of plant based sources of protein from this food group in order to ensure they are getting enough protein and other important nutrients such as iron, zinc and selenium.

  • Complete proteins in this food group include chicken, turkey, fish and other seafood, eggs, tofu, beef, pork, buffalo etc.
  • Incomplete sources of protein include beans, lentils, split peas, edamame beans, nuts and seeds. If you are a vegetarian it is important to combine these foods with other complimentary incomplete protein sources such as grain products in order to ensure you are getting all essential amino acids.

Protein powders (ie. whey or soy protein powder) will add protein to your diet however these powders are very processed and do not have a significant amount of other important nutrients. Protein powders are not necessary in order to meet your protein needs for the day and it is much better to get protein from real foods.



Amount   of Protein

Meat, fish or poultry

2 ½ oz (75g)/ ½ cup


Firm tofu

¾ cup cubed



2 large



1 ½ oz (50g)


Cooked beans, lentils & legumes

¾ cup


Cow’s milk

1 cup


Fortified soy milk

1 cup


Yogurt (plain 0%)

¾ cup


Yogurt (greek 0%)

¾ cup


Cottage Cheese

½ cup


Peanut or other nut butter spread



Nuts or seeds

¼ cup


Whole grain bread

1 slice


Pasta, rice, quinoa, barley

½ cup cooked


Hot cereal

¾ cup cooked


Cold cereal

30g (~ ¾ cup- 1 cup)



½ cup



½ cup or 1 medium fruit



How much protein do I need?

Protein isn’t only for bodybuilders, every one of all ages and gender must make sure that they are getting enough protein in order to maintain muscle mass and repair cells like those found in your muscles, skin, and nails. For those consuming a vegetarian or vegan diet, it is important to get enough vegetarian sources of protein however they do not usually need extra protein. Typically as long as you are consuming enough calories (energy) to maintain your weight, your protein needs will be met.

Current recommendations (the Recommended Dietary Allowance) for protein for adults over 19 years of age need 0.8 grams of protein per kilogram of body weight. However recent nutrition research studies have shown that current recommendations may not meet the protein needs for many Canadians and should be reassessed. Results from this study showed requirements for adults to be 1.2 grams of protein per kilogram of body weight.

Calculating your protein requirements:

  1. 1.      Weight in pounds ÷ 2.2 = weight in kilograms
  2. 2.      Weight in kilograms x 0.8**  = Average Daily Protein Need

** Multiply by 1.2 to use current research suggestion

Optimizing your protein intake

It is not only important to ensure you are getting enough protein during the day but also make sure you distribute your protein intake evenly throughout the day. Your body can only process about 30 grams of protein at a given time. Current research has shown that ideally, people should consume about 30 grams of protein at breakfast, lunch and dinner in order to optimize protein synthesis in the body. Unfortunately the typical North American diet often has very little amounts of protein at breakfast and lunch, with a large amount of protein at supper.

Ways to incorporate more protein into breakfast:

  • Have a glass of milk with your meal
  • Add nuts or seeds to your hot cereal
  • Have a hard boiled egg on the side of your cereal
  • Use almond butter or slice of cheese on your toast instead of butter
  • Make a smoothie using milk, frozen berries and Greek yogurt
  • Make an omelet with veggies
  • Have cottage cheese with fruit

Ways to incorporate more protein into lunch:

  • Add beans or lentils to your salad
  • Have a cheese string on the side
  • Add a hard boiled egg to your salad
  • Have a slice of low-fat cheese on your sandwich
  • Use hummus as a dip with raw vegetables
  • Have a side of yogurt with your meal



1. Humayun MA et al. Reevaluation of the protein requirement in young men with the indicator amino acid oxidation technique. Am J Clin Nutr 2007;86:995-1002.

2. Symons TB et al. A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects. J Am Diet Assoc 2009;109(9):1582-6.

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