Most people assume that all proteins are equal. You read the nutrition labels on foods, and you check how many grams of protein there is.
However, 3 grams of protein from one food source, like beef, is not the same as 3 grams of protein from another, like rice. That’s because not all amino acids that make up proteins can be absorbed as effectively as others.
Macronutrients
Macronutrients are nutrients that the body needs in large quantities to provide energy. The three main macronutrients are carbohydrates, proteins, and fats:
- Fats: Help the body absorb vitamins A, D, E, and K, and are important for feeling full and balancing hormones.
- Carbohydrates: Provide energy to the body and are found in foods like rice, pasta, bread, and starchy vegetables.
- Proteins: Help repair and rebuild body tissues.
Protein
Proteins are essential nutrients found in the human body and are the major structural component of all cells, including muscle, body organs, hair, and skin health.
Amino acids
Amino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are the result. The human body then uses amino acids to make proteins to help the body:
- Break down food
- Grow
- Repair body tissue
- Perform many other body functions
Amino acids are classified into three groups:
- Essential amino acids
- Nonessential amino acids
- Conditionally essential amino acids
Essential amino acids cannot be made by the body. They must come from food. Of the 20 amino acids that make up protein, 9 of them are essential.
Unlike fat and glucose, our bodies do not store proteins. If more amino acids are needed, protein will be taken from the breakdown of muscle fibers. This is why bodybuilders often consume lots of protein: to build muscle and avoid losing muscle.
Different protein food sources have different amounts of amino acids. During food processing and cooking, some of these amino acids are susceptible to damage, and so the amount of amino acids taken up by the body will vary.
DIAAS
DIAAS stands for Digestible Indispensable Amino Acid Score and is a method of measuring protein quality. It evaluates the proportion of consumed amino acids absorbed and utilized by the body.
- No protein quality claim – Score of <75%
- Good protein quality – Score ranging from 75% to 99%
- Excellent or High protein quality – Score of 100% or more
DIAAS scores of protein sources
| Protein Source | DIAAS Score (%) | Protein Quality |
|---|---|---|
| Whole Milk Powder | 143 | High |
| Milk Protein Concentrate | 118 | High |
| Whole Milk | 114 | High |
| Egg – Hard Boiled | 113 | High |
| Beef | 111 | High |
| Whey Protein Isolate | 109 | High |
| Chicken Breast | 108 | High |
| Soy Protein Concentrate | 98.5 | Good |
| Whey Protein Concentrate | 98.3 | Good |
| Pea Protein | 91.5 | Good |
| Soy Protein | 91.5 | Good |
| Wheat | 91.5 | Good |
| Soy Protein Isolate | 90 | Good |
| Chickpeas | 83 | Good |
| Pea Protein Concentrate | 82 | Good |
| Mixed Diet: Wheat, Peas and Whole Milk Powder | 82 | Good |
| Peas – Cooked | 58 | Low |
| Rice – Cooked | 59 | Low |
| Rye | 47.6 | Low |
| Barley | 47.2 | Low |
| Wheat | 40.2 | Low |
| Almonds | 40 | Low |
| Rice Protein Concentrate | 37 | Low |
| Corn-based Cereal | 10 | Low |
Notice in the table above that animal-derived protein is of high quality whereas plant-derived protein is mostly of low quality.