This quote from a popular textbook describes how the nutrients in food are essential for our physical functioning.
“Nutrients are the nourishing substances in food that are essential for the growth, development and maintenance of body functions. Essential meaning that if a nutrient is not present, aspects of function and therefore human health decline.
When nutrient intake does not regularly meet the nutrient needs dictated by the cell activity, the metabolic processes slow down or even stop.”
– Perspectives in Nutrition, Wardlow and Insel
In other words, nutrients give our bodies instructions about how to function. In this sense, food can be seen as a source of “information” for the body. See examples in Food As Information.
Thinking about food in this way gives us a view of nutrition that goes beyond calories or grams, good foods or bad foods. This view leads us to focus on foods we should include rather than foods to exclude.
Instead of viewing food as the enemy, we look to food as a way to create health and reduce disease by helping the body maintain function.