Good nutrition aims to achieve and maintain a desirable body composition and high potential for physical and mental work. Balancing energy intake with energy expenditure is necessary for a desirable body weight. Energy expenditure depends on age, sex, weight (see table Recommended Dietary Reference Intakes Recommended Dietary Reference Intakes* for Some Macronutrients, Food and Nutrition Board, Institute of Medicine of the National Academies Nutrition is the science of food and its relationship to health. Nutrients are chemicals in foods that are used by the body for growth, maintenance, and energy. Nutrients that cannot be synthesized... read more ), and metabolic and physical activity. If energy intake exceeds expenditure, weight is gained. If energy intake is less than expenditure, weight is lost.
Daily dietary requirements for essential nutrients also depend on age, sex, weight, and metabolic and physical activity. Every 5 years, the Food and Nutrition Board of the National Academy of Sciences/National Research Council and the US Department of Agriculture (USDA) issues the dietary reference intakes (DRIs) for protein, energy, and some vitamins and minerals (see also tables Recommended Dietary Reference Intakes Recommended Dietary Reference Intakes* for Some Macronutrients, Food and Nutrition Board, Institute of Medicine of the National Academies Nutrition is the science of food and its relationship to health. Nutrients are chemicals in foods that are used by the body for growth, maintenance, and energy. Nutrients that cannot be synthesized... read more , Recommended Daily Intakes for Vitamins Recommended Daily Intakes for Vitamins Vitamins may be Fat soluble (vitamins A, D, E, and K) Water soluble (B vitamins and vitamin C) The B vitamins include biotin, folate, niacin, pantothenic acid, riboflavin (B2), thiamin (B1)... read more , and Guidelines for Daily Intake Guidelines for Daily Intake of Trace Minerals Six macrominerals are required by people in gram amounts. Four cations: Sodium, potassium, calcium, and magnesium Two accompanying anions: Chloride and phosphorus Daily requirements range from... read more ). For vitamins and minerals about which less is known, safe and adequate daily dietary intakes are estimated.
Pregnant women Diet and supplements Ideally, women who are planning to become pregnant should see a physician before conception; then they can learn about pregnancy risks and ways to reduce risks. As part of preconception care... read more and infants Nutrition in Infants If the delivery was uncomplicated and the neonate is alert and healthy, the neonate can be brought to the mother for feeding immediately. Successful breastfeeding is enhanced by putting the... read more have special nutritional needs.
The USDA publishes MyPlate, which helps people develop a healthy eating style and make healthy food choices that suit their individual needs. The recommendations are individualized based on age, sex, and physical activity.\
Generally, the recommended intake decreases with aging because physical activity tends to decrease, resulting in less energy expended.
The the following general guidelines are emphasized for adults and children:
Adequate fluid intake is also important.
Fats should constitute ≤ 28% of total calories, and saturated and trans fatty acids should constitute < 8%. Excess intake of saturated fats contributes to atherosclerosis. Substituting polyunsaturated fatty acids for saturated fats can decrease the risk of atherosclerosis.
Routine use of nutritional supplements is not necessary or beneficial; some supplements can be harmful. For example, excess vitamin A can lead to hypervitaminosis A, with headaches, osteoporosis, and rash.