Food is a mixture of chemicals. The essential chemicals are nutrients. Other chemicals found in food are flavors, colors, caffeine, and phytochemicals (plant chemicals that are important to health functions).
There are 6 essential chemicals, or nutrients: carbohydrates, lipids (fats and oils), proteins, vitamins, minerals, and water. They all contribute to cell and body structure and regulate body processes. Carbohydrates, lipids, and proteins supply energy.