What is protein?
Protein is made up of building blocks called amino acids. While our bodies can make most of the 20 amino acids we need, some can only come from the food we eat.
Our bodies use the amino acids in protein-rich foods to make proteins required to perform many functions throughout our bodies – in fact, they're a vital of part of literally every cell in your body.
Protein's main function is to build, maintain and repair all your body's tissue, such as muscles, organs, skin and hair. Protein can also be used as energy by your body, but this usually only happens when carbohydrate and fat stores are in short supply.
Eating a variety of protein-rich foods throughout the day helps ensure you're getting the balanced combination of the amino acids your body needs. If you eat more protein than your body needs, it tends to get broken down and stored as fat, not protein.
Recommended Dietary Allowance (RDA)
Infants 7-12 months: 1.2 g protein for each kg of body weight/day (about 11 g protein/day)
Children 1-3 yrs: 1.05 g/kg/day
Children 4-13 yrs: 0.95 g/kg/day
Adolescents 14-18 yrs: 0.85 g/kg/day
Adults 19-70+ yrs: 0.8 g/kg body weight (about 63 g/day for an average adult male, and 53 g/day for an average adult female)
Pregnancy (second-half): 1.1 g/kg/day (for the first half of pregnancy, protein requirements are the same as for non-pregnant women)
Lactating women: 1.3 g for each kg/day
Top dietary sources
| Food Item |
Serving Size |
Total Protein (g) |
| Beef, lean steak |
75 g |
21 |
| Chicken breast |
75 g |
24 |
| Halibut |
75 g |
20 |
| Egg |
large |
6 |
| Milk |
250 ml |
9 |
| Cheddar or mozzarella cheese |
30 g |
8 |
| Low fat yogourt |
100 g |
5 |
| Kidney beans |
125 ml |
8 |
| Firm tofu |
100 g |
16 |
| Almonds |
50 ml |
5 |
References:
Complete Food & Nutrition Guide, 2nd edition, American Dietetic Association
Dietary Reference Intake Tables, Health Canada
Nutrient Value of Some Common Foods, Health Canada
