Meat, fish, poultry, eggs, milk, cheese, yogurt and soybeans provide all nine essential amino acids. For this reason, they are considered high quality or complete
Plant sources of protein include legumes (dried beans, peas, and lentils), nuts, and seeds. Grain products such as barley, wheat, millet, rye, as well as many vegetables, have smaller amounts of protein. These plant sources are all incomplete
proteins because they don't contain all the nine essential amino acids that the body needs.
Luckily, the essential amino acids present in one plant food can "connect" with the essential amino acids in another plant food to form a complete protein. This is the principle used to make a vegetarian diet. There is no need for combining specific foods at each meal, as once thought. Your body can make its own complete proteins if you eat a variety of plant foods and eat enough calories throughout the day. (For more on how to make sure you get all your important nutrients with a vegetarian diet, click here.
The recommended protein intake for adults is 56 grams each day for a healthy male and 46 grams each day for a healthy female. But during pregnancy, that recommended intake increases to 71 grams of protein to handle the additional growth and development. Use the following steps to determine your specific protein needs: