Maintaining a healthy diet is the practice of making choices about what to eat with the intent of improving or maintaining good health. Usually this involves consuming necessary nutrients by eating the appropriate amounts from all of the food groups. Since human nutrition is complex a healthy diet may vary widely subject to an individual's genetic makeup, environment, and health. For around 20% of the planet's population, lack of food and malnutrition are the main impediments to healthy eating.
Generally, a healthy diet will include:
1. Sufficient calories to maintain a person's metabolic and activity needs, but not so excessive as to result in fat storage greater than roughly 12% of body mass;
2. Sufficient quantities of fat, including monounsaturated fat, polyunsaturated fat and saturated fat, with a balance of omega-6 and long-chain omega-3 lipids;
3. Avoidance of saturated fat.
4. Sufficient essential amino acids ("complete protein") to provide cellular replenishment and transport proteins;
5. Essential micronutrients such as vitamins and certain minerals.
6. Avoiding directly poisonous (e.g. heavy metals) and carcinogenic (e.g. benzene) substances;
7. Avoiding foods contaminated by human pathogens (e.g. e. coli, tapeworm eggs);
8. Avoiding chronic high doses of certain foods that are benign or beneficial in small or occasional doses, such as
* foods or substances with directly toxic properties at high chronic doses (e.g. ethyl alcohol); * foods that may interfere at high doses with other body processes (e.g. table salt); * foods that may burden or exhaust normal functions (e.g. refined carbohydrates without adequate dietary fibre).
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