俗语说："病从口入。"可见饮食与人们的健康是息息相关的。吃了什么对于人体的健康非常重要。合理的饮食充足的营养，能提高一代人的健康水平，预防多种疾病的发生发展，延长寿命，提高民族素质。不合理的饮食，营养过度或不足，都会给健康带来不同程度的危害。如何合理饮食才能维护健康、预防疾病、保持生命的活力，成为当今社会日常生活中刻不容缓要解决的问题。(There is a saying that "disease enters by the mouth". It is thus clear that the diet is closely linked to the health of people. What to eat is very important to human's health. Reasonable diet and adequate nutrition may improve the health level of one generation; prevent the occurrence and development of several diseases; extend the life and enhance the national quality. Unreasonable diet and overnutrition or undernutrition all may bring about different levels of damage to the health. How to reasonably eat a diet to maintain the health, prevent the disease and keep the life vitality becomes the problem which needs to be solved with admit of no delay in the daily life of today's society.)