It is a wrong concept to avoid just meat and meat products when going green, without paying attention to the importance of replacing them by sufficient plant proteins! Many vegetarian beginners do not feel satiated when having meatless meals, so they unconsciously fill their stomachs with more carbohydrate-rich foods (e.g. rice, noodles, bread, etc), potentially resulting in weight gain. And because of the sudden surge in blood sugar level, they become tired and sleepy soon after the starchy meals. Apart from being involved in body cell production and repair, proteins in food actually provide you with more long-lasting satiety than carbohydrates and fats do. Therefore, if you are able to consume enough proteins during main meals, you are less likely to feel hungry and have snacks between meals, that is important for weight control.
Complete Protein VS Incomplete Protein
There are nine types of amino acids which we must obtain from foods. Proteins with all these essential amino acids are known as “complete proteins”. Majority of the plant-based foods lack one or more essential amino acids and therefore, plant proteins are usually “incomplete proteins”. In the past, it was recommended to get all the essential amino acids by including complementary proteins – having different types of plant-based foods to compensate the essential amino acid(s) that each food lacks. One example is to have rice and beans together in one meal. However, the updated recommendation is to consume different plant foods (e.g. legumes, nuts, seeds, grains and vegetables) throughout a day to obtain all essential amino acids, provided that the caloric requirements are met. In other words, diversity is the key.
Protein Requirement
| Age |
Recommended Dietary Allowance for Protein |
| 0 – 6 months |
9.1g |
| 6 – 12 months |
11g |
| 1-3yr |
13g |
| 4-8yr |
19g |
| 9-13yr |
34g |
| 14-18yr |
（Male）52g （Female）46g |
| 18yr above |
（Male）56g （Female）46g |
| Pregnant and lactating women |
71g |
（Source: Institute of Medicine, US）
The above recommended values are rather rough estimations. For a more accurate calculation, one’s body weight will be taken into account:
| |
Protein Requirement per Body Weight (kg) |
| Adult |
0.8-1g |
| Elderly |
1-1.2g |
For example, the estimated protein requirement for a 50-kg healthy adult will be 40-50g. As the amount of body protein loss increases while the ability to digest and absorb food substances decreases with age, elderly people have increased protein needs. Moreover, one’s protein requirement should be adjusted based on different conditions, such as physical activity level, underweight/overweight and medical conditions.
Sources of Plant Proteins
Legumes (e.g. lentils and red kidney beans), soy products, nuts and seeds are natural protein-rich foods. Eat Smart Tips:
- We normally count 7g of protein as one serving. For adult, it is ideal to have 2 servings of protein for each meal.
- Although nuts and seeds are protein-rich, their fat and energy contents are relatively high. Keep an eye on the amount consumed!
