Nutrients are identified as substances within food, which the human body uses to sustain its growth. Nutrients also provide the body with means to maintain and repair itself. There are three main types of nutrients; carbohydrates, lipids, and proteins. These three main nutrients constitute a large amount of the food we eat. Vitamins and minerals are also considered to be nutrients, though they are not required in the same amount, as are lipids, proteins and carbohydrates. Water is also considered to be a nutrient. Water is approximately 60% of the food volume, which we eat. Thus, water is the most plentiful nutrient within the human body. Most foods contain a variety of different nutrients.

Carbohydrates are mostly composed of sugars, as well as starches. The three main carbohydrates are glucose, fructose and galactose. Most carbohydrates are derived from plants. Lipids are derived from animal products. The two most prominent lipids are cholesterol and phospholipids. Proteins are mainly acquired through animal products. Proteins are mainly amino acid polymers. Vitamins are organic nutrients. Vitamins are essential to bodily well being, due to the fact that some vitamins contain anti-cancer components. The main minerals are calcium, phosphorus, potassium, sulfur, sodium, chloride, and magnesium.