A well-nourished child is a child ready to learn. Kids that are fit are more likely to have the energy, stamina and self-esteem that enhance their ability to learn.
Healthful eating, both Breakfast and Lunch; along with regular physical activity, helps kids get and stay fit. Severe nutrient deficiencies are linked to many issues: improper growth, mental development and very low energy levels. These things will have an impact on a child's ability to learn.
For example, iron deficiency among children leads to poor behavior, difficulty concentrating, and poor performance. Choose lunch meal options that include a variety of foods from all the food groups. Lean meats and low-fat dairy for protein, whole wheat or whole grain servings of breads and grain for energy from carbohydrates and a variety of fruits and vegetables, preferably fresh, to round out the meal. Eating from a variety of foods gives one a full complement of the essential vitamins, minerals and nutrients essential for growth and development.
As a Registered Dietitian, I must emphasize that a child will do his/her best in school if three regular meals are consumed daily along with healthy snacks. You just cannot teach a hungry child.