As recently as the 1960s doctors told their patients that nutrition had little to do with their health. Now we know otherwise: "you are what you eat!" More specifically, in humans, the matter which comprises the cells of the body (except those cells produced before birth) is acquired from food in the stomach. Not all the food matter in the stomach can be used for the body; the matter that is left over as waste is removed.

Study in this field must take into account the state of the animal before ingestion and after digestion as well as the chemical content of the food and the waste. The specific types of matter (chemicals) that are absorbed by the body can be determined by comparing the waste to the food. The effect that the absorbed matter has on the body can be determined by finding the difference between the pre ingestion state and the post digestion state.

The effect may only be discernible after an extended period of time in which all food and ingestion must be exactly regulated and all waste must be analyzed. The number of active variables involved in this type of experimentation is very high. This makes scientifically valid nutritional study very time consuming which accounts for why a proper science of human nutrition is rather new.

Table of contents

1 Nutrition and health 2 Advised dietary guidelines, and concepts in nutrition 3 Current issues and controversies 4 See also 5 External links 5.1 Nutritional data 5.2 Further reading

Nutrition and health

There exists a many diseases which are thought to be directly related to nutrition (see Dr. Joel Fuhrman). These include:

• heart disease (Leading cause of death in USA)
  • Caused by saturated fat and trans fat
• Some cancers
• diabetes
• beriberi
• rickets
• scurvy
• vitamin deficiency disease
• kwashiorkor
• pellagra
• poor immune system function, potentially leading to a wide range of other illnesses.
• osteoporosis
  • Caused by calcium deficiency

• metabolic or nutritionally related disease such as diabetes or endemic goitre.
• various eating disorders such as binge eating, anorexia nervosa, or bulimia

Current dietary guidelines in the United States are presented in the concept of a food pyramid. Detailed information on general nutrition is available at the Department of Agriculture's Food and Nutrition Information Center, at http://www.nal.usda.gov/fnic/.

Some concepts in nutrition include these need to be filled out:

• calorie
• vitamins and minerals
• proteins
  • essential amino acids
  • limiting amino acid and net protein utilization
• fats
  • saturated fat
• carbohydrates (see: Glycemic Index)
  • sugars
  • starches
• dietary fiber
• cholesterol
  • HDL cholesterol or "good" cholesterol (related to unsaturated fat)
  • LDL cholesterol or "bad" cholesterol (related to saturated fat)
• elimination diets

• The current disparity in food availability between first and third world populations, see famine and poverty
• How large a place dairy products should take in the food pyramid
• Why does an increase in the plant content of our diet seem to reduce the risk of developing some chronic illnesses? (See BNF link below)
• What has been called the phytochemical revolution.
• How much meat and animal products is appropriate in diet, see also vegetarian and vegan
• How essential to proper digestion are the enzymes contained in food itself, which are usually destroyed in cooking (see Living foods diet)
• Should genetic engineering be used in the production of food crops and animals
• Are the use of pesticides, and fertilizers damaging to the foods produced by use of these methods, see also organic farming
• nutritional supplements in the form of pills, powders, liquids
• herbal supplements in the form of pills, powders, liquids
• use of antibiotics and hormones in animal farming

• Eating disorders
• Food faddism
• Metabolism
• Veganism
• Vegetarianism

• USDA food composition search engine food data
• Daysworth meal nutrition calculator meal data

• British Nutrition Foundation: Advice and news on nutrition
• Nutrition Low Down: food facts based on the USDA database