Nutrition, nourishment, or aliment, is the supply of materials - food - required by organisms and cells to stay alive. In science and human medicine, nutrition is the science or practice of consuming and utilizing foods.

In hospitals, nutrition may refer to the food requirements of patients, including nutritional solutions delivered via an IV (intravenous) or IG (intragastric) tube.

Nutritional science studies how the body breaks food down (catabolism) and repairs and creates cells and tissue (anabolism) - catabolism and anabolism = metabolism. Nutritional science also examines how the body responds to food. In other words, "nutritional science investigates the metabolic and physiological responses of the body to diet".

As molecular biology, biochemistry and genetics advance, nutrition has become more focused on the steps of biochemical sequences through which substances inside us and other living organisms are transformed from one form to another - metabolism and metabolic pathways.


Nutrition also focuses on how diseases, conditions and problems can be prevented or lessened with a healthy diet.

Nutrition also involves identifying how certain diseases, conditions or problems may be caused by dietary factors, such as poor diet (malnutrition), food allergies, metabolic diseases, etc.
What is the difference between a dietician and a nutritionist?

A dietician studied dietetics, while a nutritionist studied nutrition. The two terms are often interchangeable, however they are not 100% identical.
  • Dietetics: the interpretation and communication of the science of nutrition so that people can make informed and practical choices about food and lifestyle, in both health and disease. Part of a dietician's course includes both hospital and community settings. The majority of dieticians work in health care, education and research, while a much smaller proportion also work in the food industry. A dietician must have a recognized degree (B.Sc. or M.Sc), or postgraduate degree in nutrition and dietetics to work as a dietician.
  • Nutrition: the study of nutrients in food, how the body uses nutrients, and the relationship between diet, health and disease. Major food manufacturers employ nutritionists and food scientists. Nutritionists may also work in journalism, education and research. Many nutritionists work in the field of food science and technology.
There is a lot of overlap between what nutritionists and dieticians do and studied. Some nutritionists work in health care, some dieticians work in the food industry, but a higher percentage of nutritionists work in the food industry and food science and technology, and a higher percentage of dieticians work in health care.