This usually involves consuming nutrients by eating the appropriate amounts from all of the food groups, including an adequate amount of water. Since human nutrition is complex, a healthy diet may vary widely, and is subject to an individuals genetic makeup, environment, and health.
Sufficient calories to maintain a person's metabolic and activity needs, but not so excessive as to result in fat storage greater than roughly 30% of body mass. For most people the recommended daily allowance of energy is 2,000 calories, but it depends on age, sex, height, and weight. Sufficient quantities of fat, including monounsaturated fat, polyunsaturated fat and saturated fat, with a balance of omega-6 and long-chain omega-3lipids. The recommended daily allowance of fat is 65 grams.
Maintenance of a good ratio between carbohydrates and lipids (4:1): four grams of the first for one gram of the second.
Avoidance of trans fat: Sufficient essential amino acids ("complete protein") to provide cellular replenishment and transport proteins. (All essential amino acids are present in animals. Some plants together give all the essential acids except rice and beans which have limitations.)
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. refined table salt);foods that may burden or exhaust normal functions (e.g. refined carbohydrates without adequate dietary fiber).