Our bodies require seven types of nutrients to function well - carbohydrates, proteins, fats, vitamins, minerals, fibre and water – but in different quantities. In this, guides like the Healthy Eating Pyramid are invaluable as it sits on a foundation of regular exercise and weight control. Generally, the pyramid encourages you to consume less of the foods at the top (e.g. red meat, butter, salt and sugary drinks) and more of the ones at the bottom (e.g. whole grains, fruits, and vegetables).

The Mediterranean Diet, Latin American Diet, Asian Diet and Vegetarian Diet pyramids are also good, flexible guides to healthy eating. These take into consideration the traditions of people living within those regions that have contributed to their good health. For example, the Mediterranean Diet pyramid recommends making olive oil your primary source of dietary fat, while the Asian Diet pyramid recommends six glasses water or tea daily.

Another meaning for diet is a regimen to promote weight loss. Examples of these diets are Atkins (emphasizing intake of less carbohydrates, more protein), South Beach, and Weight Watchers points system.