The main component of rice and noodles is carbohydrates, which is a nutrient that is both economical and can be directly converted into heat energy. In a balanced diet, 50% to 60% of the total daily energy requirement comes from staple foods. Nutritionists recommend a scientific and rational combination of staple and non-staple foods, such as pairing rice with vegetables and meat dishes with fruits. Of course, the ratio of staple to non-staple foods also varies across different age groups.