Introduction: When grains and soybeans are combined, a "complementary effect" occurs, which significantly improves protein absorption.
The term "grain" here actually refers to all grains, including rice and wheat products, such as rice congee, steamed buns, and noodles. "Beans" refers to legumes, including soybeans, mung beans, and red beans, as well as products made from them like soy milk, dried tofu, and tofu. Although both types of food are very nutritious, each has its own deficiencies. For example, grains are low in lysine but high in methionine, while beans are high in lysine but low in methionine. When eaten alone, the protein from either is not well absorbed. However, when paired, they create a "complementary effect," greatly improving protein absorption to the level of meat protein. This is the saying: "Grains plus beans equals eating meat."
This does not mean, however, that you can simply have soy milk in the morning and rice at noon. For the "grains and beans" combination to be most effective, they must be cooked together. For instance, adding some rice when making soy milk, adding some beans when congee, or adding soy milk when cooking rice or congee. This not only makes the flavor richer but also maximizes the nutritional value. A slightly less effective combination is to eat "grains and beans" in the same meal, such as pairing a steamed bun with dried tofu, or having soy milk with a steamed bun.