A third reason we need food, says Food and Nutrition, is “to regulate the health of the body . . . and prevent disease.” The health benefits of good food are not immediately obvious. When we finish a good meal, we seldom think, ‘That has done my heart (or my kidneys or my muscles, and so on) a world of good.’ Yet, try to do without food for an extended period of time, and the consequences to your health become obvious. What consequences? “The commonest picture,” says one medical reference work, “is a negative one: failure to thrive, failure to resist trivial infection, lack of energy or initiative.”

Food and Nutrition, a textbook that discusses the importance of having a proper diet, gives us three good reasons for eating well. One is that we need food “to promote growth and to make good the wear and tear on body cells.” Did you know that each day of your life, a trillion of your body cells are broken down and need to be replaced? Proper growth and body maintenance require good food.

Food is also needed “to produce heat and energy.” Food provides the fuel for our bodies to function well. If we eat poorly, we will have little energy. Lack of iron in our diet can leave us feeling tired and lethargic.