There are six classes of nutrients required for the body to function and maintain overall health. These are: carbohydrates, lipids, proteins, water, vitamins, and minerals. Nutritious foods provide nutrients for the body including phytonutrients that are nutrients derived from plant sources.     Foods may also contain a variety of non-nutrients. 

Nutrients that are needed in large amounts are called macronutrients. There are three classes of macronutrients: carbohydrates, lipids, and proteins. Macronutrients are carbon-based compounds that can be metabolically processed into cellular energy through changes in their chemical bonds. The chemical energy is converted into cellular energy known as ATP, that is utilized by the body to perform work and conduct basic functions.

The amount of energy a person consumes daily comes primarily from the 3 macronutrients. Food energy is measured in kilocalories. For ease of use, food labels state the amount of energy in food in “calories,” meaning that each calorie is actually multiplied by one thousand to equal a kilocalorie. (Note: Using scientific terminology, “Calorie” (with a capital “C”) is equivalent to a kilocalorie. Therefore: 1 kilocalorie = 1 Calorie - 1000 calories.

Consuming alcohol also contributes energy (calories) to the diet at 7 kilocalories/gram, so it must be counted in daily energy consumption.

There is one other nutrient that we must have in large quantities: water. Water does not contain carbon.  It is composed of two hydrogen atoms and one oxygen atom per molecule of water.  More than 60 percent of your total body weight is water.  Without water, nothing could be transported in or out of the body, chemical reactions would not occur, organs would not be cushioned, and body temperature would widely fluctuate. 

Micronutrients are also essential for carrying out bodily functions, but they are required by the body in lesser amounts.  Micronutrients include all the essential minerals and vitamins. There are sixteen essential minerals and thirteen essential vitamins.

In contrast to carbohydrates, lipids, and proteins, micronutrients are not sources of energy (calories) for the body.  Instead they play a role as cofactors or components of enzymes (i.e., coenzymes) that facilitate chemical reactions in the body.  They are involved in all aspects of body functions from producing energy, to digesting nutrients, to building macromolecules.  Micronutrients play many essential roles in the body.
Phyto-nutrients are plant sourced nutrients.