Agriculture Reference
In-Depth Information
T A B L E 2.1. General Energy and Nutrient Needs of Children and Adults
Energy
Calories (kcal)
Protein
(g)
Carbohydrate
(g)
Fat
(g)
Fiber
(g)
Person
Growing child (20 kg)
1800
45 - 68
247 - 337
30 - 60
27 - 40
Nongrowing male adult (80 kg)
2900
73 - 109
399 - 544
48 - 97
27 - 40
Nongrowing female adult (60 kg)
2000
50 - 75
275 - 375
33 - 67
27 - 40
Source: Calculated from WHO Technical Report Series 916, Table 6. Available at http://WHO.int/
publications/en/and data available in Bibliography.
essential in that the human body cannot make them and thus need to be part of the food
intake. Both of these issues are discussed below.
People around the world obtain their food from different locally available sources,
and this is sufficient as long as the total of their diet contains all the essential
components and contains them in proportions that the body needs. A diet containing
a mix of carbohydrate and protein-rich foods along with some fat, oil, and fiber, particu-
larly from fruit and vegetables, is probably sufficient. This is particularly true if the diet
contains mixed food sources, that is, grains, root crops, meat, vegetables, fruits, berries,
and nuts. However, it is likely not to be true if the diet consists of only one food type
such as meat or a single type of grain or root crop.
It is possible for people to obtain some of their needed minerals such as calcium
and iron from nonfood sources, such as salt, and those minerals dissolved in drinking
water and eating minerals such as calcium carbonate. However, it is generally agreed
that these sources are not as readily absorbed by the body during the digestion
process as are those available from food.
In more specific terms what does the human body need from food and how does it
use these needed foods? It needs energy, most often provided by carbohydrates, protein
to build and maintain muscle, fat and oil for both energy and cellular membranes, vita-
mins to augment enzyme activity, and minerals for teeth, bones, and enzyme activity.
As shown in Table 2.1, the amounts of each of these will depend on age, size (body
weight), level of activity, climate, and heredity.
2.3
ENERGY
Carbohydrates are the most common source of metabolic energy around the world. Four of
the more common carbohydrate-rich foods are rice, maize, potato, and cassava, as shown
in Figure 2.6, and are considered staple foods. Wheat, which is not shown, is also
very important. These can be cooked in various ways and are often the bulk of the meal.
As seen in Table 2.1, the human body needs energy. Several significant things about
this need are not generally recognized. One is that a lack of energy can substantially
reduce the development of children and the health of adults. Second, all food, except
minerals and fiber, can be used as a source of energy if insufficient energy is supplied
by carbohydrates or fat. This means that other components of the diet will not be available
to be used for other essential bodily needs such as muscle development. For this reason an
appropriate intake of energy-rich foods is essential for normal growth and health.
