Nutritional Needs for adults males and females

A general definition of a balanced diet is food intake that not only includes all the dietary needs of the organism (person), but includes the required dietary components, e.g. water, carbohydrates, proteins, dietary fibre, etc., in the correct proportions. That leads to questions about what, exactly, a person's dietary needs are - and, of course, what are the correct proportions. General answers to these questions are usually for a "normal, healthy adult" assumed to be neither pregnant or lactating, nor elderly.

A healthy diet includes carbohydrates, proteins, fats, dietary fibre, water, vitamins and minerals - but how much of each ?

A person's dietary needs change as he or she passes through the different stages of life from birth to childhood, to adulthood and eventually later life. Dietary needs change in terms of the amount (energy value) and type (nutritional content) of foods required for good health.

An important general principle is that more energy is required to support periods of growth and to fuel active lives - regardless of whether the activity is part of a working lifestyle e.g. agriculture or fishing in harsh environments, pursued for leisure e.g. amateur sports and physical recreation, or is just a healthy aspect of growing-up.

Short notes about dietary requirements at the main human life stages follow below:

Human Life Stages		Notes:
1.	Newborn babies - first 6 mths	Breast milk is the most natural food for newborn babies and provides a "total food" for a baby for up to about the first 6 mths of life.
		In the first 12 months of life a baby's energy requirement can be up to 3 times (200% greater) than the proportional - to size - needs of an a typical adult. Similarly, a young baby's needs compared with that of an adult are estimated:
		3x energy need 3x protein need 3x need for B vitamins 4x need for vitamins A, C and D and the minerals calcium & iron.
2.	Toddlers & Young Children (approx 1 - 11 years)	School children grow quickly and are generally very active. Their energy and nutritional requirements are therefore proportionally (by body mass) greater than those of adults.
3.	Puberty & Adolescence (approx 11 - 19 years)	Young people experience much physical development in the form of growth (increase in size and total mass) and other changes incl. e.g. hormonal during their pre-teen and teenage years. Their nutritional needs therefore differ from those of adults and are also different for male and female adolescents.
3.	Puberty & Adolescence (approx 11 - 19 years)	Energy requirement may be up to 80% higher than when adult Protein requirement may be up to 80% higher than when adult May need more vitamin C than when adult Females may have increased requirement for iron Males may have increased requirement for calcium - for thickening bones

4.	Adulthood	The dietary requirements of a "normal" or "average" adult are the most often cited "typical" human dietary needs. However, there are variations - esp. re. energy requirement - between men and women, depending on body mass, and according to activity levels e.g. due to highly physical occupations or pursuits vs sedentary lifestyles. Overall, an adult's energy requirement may vary by 100% depending on such variables. See also metabolic rate.
5.	Pregnancy	Pregnancy changes the proportions in which energy and some nutrients are required. Some changes include:
		10% increase in energy requirement 10% increase in protein requirement 100% increase in vitamin C, calcium and folic acid requirements.
		However, high doses of some nutritional supplements e.g. certain vitamins are not recommended in pregnancy due to possible effects on the foetus.
6.	Lactation (Breast feeding mothers)	There are additional energy and nutritional requirements when breast feeding, e.g.
6.	Lactation (Breast feeding mothers)	20% increase in protein and iron requirements 25% increase in energy requirement 25% increase in requirement for B vitamins 100% increase in requirement for vitamins A and C 150% increase in calcium requirement - so more vitamin D also needed
7.	Later life, elderly people (60+ years, depending on general health)	Depending on their lifestyle activity level, elderly people may have reduced needs for energy (and associated B vitamins) and protein by 25-30%, or possibly more in the case of very sedentary lifestyles. Due to their reduced energy requirement elderly people may naturally eat less than when they lead more active lives. If this reduction in quantity of food results in insufficient intake of natural vitamin C in fresh fruits and vegetables, elderly people may benefit from vitamin C supplements. Elderly people and especially elderly women may be found to be at risk of osteoporosis and so benefit from supplementation of calcium and vitamin D.

Note: The numbers in this table are for ease of reference to and discussion of this table only. Human life stages can equally be described in terms of more or fewer categories depending on the reason for defining the stages and the level of detail of study.

Dieticians and nutritionists can describe dietary requirements for people according to their life stage or situation, such as:

	The following situations are not necessarily stages in life but are situations that give rise to specific dietary considerations:
	dietary needs for babies dietary needs for infants dietary needs for toddlers dietary needs for children dietary needs for school children dietary needs for teenage girls dietary needs for teenage boys dietary needs for teenagers dietary needs for adults dietary needs for women dietary needs for men dietary needs for pregnant women dietary needs for pregnancy and breastfeeding dietary needs for breastfeeding dietary needs for the elderly dietary needs for old people dietary needs for older people	dietary needs for a diabetic (person) dietary needs for coeliacs dietary needs for diabetics dietary needs for diverticulitis dietary needs for hypertension dietary needs for lactose intolerance dietary needs for obese people dietary needs for obesity dietary needs for stress dietary needs for specific activities (e.g. dietary needs of swimmers etc.) dietary needs for vegetarians dietary needs for vegans dietary needs for weight loss dietary needs for young athletes

* Correct English grammar would require the above phrases to take the form "dietary needs of [children, etc.]". However, recent research indicates that more internet users search for "dietary needs for [children, etc.]" than use the grammatically correct form. The intention is obviously equivalent.