O level Notes : Food Technology Design - Meal Planning And Food Service - Choosing dishes according to nutritional requirements

It is a challenge to every meal planner to meet individual nutritional requirements, hence the need to have a sound knowledge in nutrition in order to come up with healthy meals.  The appearance of the meal is vital as it helps stimulate appetite, therefore great effort is needed towards choice of attractive meals. Careful planning and timing of activities makes the cooking of meals interesting and efficient. In this chapter we shall discuss some guidelines on choice of dishes, drawing up a time plan and compiling a shopping list.

Planning meals according to nutritional requirements

Nutritional requirement is the amount of each nutrient needed by the body. The individual nutritional requirement is determined by a person's age, gender, body size, growth, pregnancy or breastfeeding, illness, level of activity, and psychological and emotional stress.

Each nutrient has a particular series of functions in the body and some nutrients are needed in large quantities than others. For example, adolescences need more protein than adults to cater for the spurt growth. Failure to meet individual nutritional requirements may also lead to nutritional disorders and diseases. To meet the body's regular nutritional needs, one should consume:

• a wide variety of nutritious foods.
• plenty of water on a daily basis.
• enough kilojoules for energy, with carbohydrates as the preferred source.
• essential fatty acids from foods such as oily fish, nuts, avocado.
• adequate protein for cell maintenance and repair.
• fat-soluble and water-soluble vitamins.
• essential minerals such as iron, calcium and zinc.
• Foods containing plant-derived phytochemicals, which may protect against heart disease, diabetes, some cancers, arthritis and osteoporosis.
• A varied diet that concentrates on fruits, vegetables, wholegrain or high fibre cereal varieties such as breads, cereals, rice, pasta, noodles, polenta, couscous, oats, quinoa and barley.
• lean meats and poultry, fish, eggs, tofu, nuts and seeds, and legumes/beans
• Milk, yoghurt,  cheese  and  or  their  alternatives,  mostly  reduced  fat.However, reduced-fat varieties are not suitable for children under two years of age.

• Children should not be offered discretionary foods (these are foods that you decide when and how they should be eaten) every day, as they are poor sources of important nutrients. Children need adequate nutrients for growth and development. 'Discretionary' foods and drinks include sweet biscuits, cakes, desserts and pastries, processed meats and fattier or salty sausages, sweetened condensed milk, ice cream and other ice confections, confectionary and chocolate. Also includes savoury pastries and pies like commercial burgers  with  a  high  fat  and  or  salt  content. As  well  as commercially fried foods such as potato chips, crisps and other fatty and or salty are dicretionary. Snack foods including cream, butter and spreads which are high in saturated fats, sugar-sweetened soft drinks and cordials, sports, energy drinks and alcoholic drinks are part of the discretionary foods.

Nutritional requirements at different life-stages

As we age, our nutritional requirements continue to change according to the need of calories, proteins, vitamins, and minerals. Nutritional requirements vary for each nutrient and also differ between individuals and life stages for example women of childbearing age need more iron than men. It is therefore important to take into account the extra demands placed on the body by these changes.

Infants (0 to 12 months)

The first 4-6 months of life is a period of rapid growth and development. Breast milk and infant formula generally supplies a baby with the required amounts of nutrients, fluids and energy up to about six months of age. It is recommended that infants be exclusively breastfed up to around six months of age.

Occasional exposure of the skin to sunlight is usually enough to provide a baby's vitamin D requirements, but this does vary from season to season and with skin colour. Breast milk is preferred to infant formula where possible, as it contains many protective and immunological factors that benefit the baby's development. Breast milk or correctly prepared infant formula provides enough water for a healthy baby to replace any water losses. However, all babies need extra water once solid foods are introduced.

During the early months of life, babies can draw upon iron stores they have accumulated before birth but these stores are rapidly depleted and it is important that the diet given during weaning contains enough iron to meet the baby's needs for growth and development. Requirements for protein, thiamine, niacin, vitamin B6, vitamin B12, magnesium, zinc, sodium and chloride also increase between 6 and 12 months.

As a baby is gradually weaned from the breast or bottle and new solids are introduced, there may be reduced body stores of iron. To maintain nutrient body iron stores, give the baby foods that are rich in iron and zinc, such as iron-enriched infant cereals, pureed meats and poultry dishes, and cooked plain tofu and legumes/soy beans/lentils.

Toddlers (aged 1 – 3 years)

From around 12 months onwards, offer toddlers a wide variety of healthy meals and snacks enjoyed by the rest of your family. Offering a wide range of foods to toddlers ensure adequate nutrition.

Energy requirements increase because children are active and growing rapidly. Protein requirements does not increase much. There is an increased need for all the vitamins, except vitamin D (some of which will now be synthesised in the skin, following sunlight exposure). Slightly lower amounts of calcium, phosphorus and iron are needed. There is an increased requirement for all the other minerals except for zinc.

In the second year of life, children continue to need energy-dense diets. They should be given whole milk, not skimmed or semi skimmed. Reduced-fat milks are not recommended for children under the age of two, due to increased energy requirements and high growth rate at this age.

Care needs to be taken over the amount of dietary fibre eaten by toddlers, if the diet is too bulky due to too many high fibre foods, there is a danger that the child will be unable to eat enough food to satisfy its energy needs. These need to be given in moderation.

Young children (aged 4-6 years)

Energy requirements continue to increase and there is a greater need for protein, all the vitamins (except C and D) and all the minerals (except iron).

Food-related problems for young children include overweight, obesity, tooth decay and food sensitivities. If a child is gaining inappropriate weight for growth, limit energy- dense and nutrient-poor snack foods. Increase the child's physical activity and limit the amount of television watching. Tooth decay can be prevented by avoiding sugary foods and drinks, especially if sticky or acidic. Ensure the child has enough fluids, especially water. Fruit juices should be limited and soft drinks avoided.

School- aged children (aged 7-10 years)

Poor nutrition compromises both the quality of life of school-aged children and also their potential to benefit from education. They should eat three well balanced meals a day and two nutritious snacks.

School-aged grow significantly but at a slower rate whilst being very physically active. Hence their nutritional needs are high and critical. There is a marked increase in requirements for energy and protein. No change in the requirement for thiamin, vitamin C or vitaminAbut the requirements for the other vitamins and minerals are increased.

During childhood, children tend to vary their food intake (spontaneously) to match their growth patterns. Children's food needs vary widely, depending on their growth and their level of physical activity.

Ideally, children should be accumulating stores of nutrients in preparation for the rapid growth spurt experienced during adolescence so a balanced diet is important. Appropriate weight gain and development will indicate whether food intake is appropriate.

Adolescence 11-19 years

Adolescence is characterised by growth spurt, a period in which growth is very fast. It is the transitional phase of growth and development between childhood and adulthood. Adolescents are children entering their teenage years. For girls, this generally occurs around 10 to 11 years of age. For boys, it occurs later, at around 12 to 13 years.

The rapid physical changes of adolescence have a direct influence on a person's nutritional requirements. Any nutritional deficiency experienced during this critical period of life can have an effect on the future health of the individual and their off spring.

By the age of 11, the vitamin and mineral requirements for boys and girls start to differ.

Boys - Energy and protein requirements continue to increase as do the requirements of a number of vitamins i.e. thiamin, riboflavin, niacin, vitamins B6, B12, C and A; and magnesium, potassium, zinc, copper, selenium and iodine. Calcium requirements remain high as skeletal development is rapid.

Girls - Requirements for energy, protein, thiamin, niacin, vitamins B6, B12   and C, phosphorus, magnesium, potassium, copper, iron, selenium and iodine all increase.

• The extra energy required for growth and physical activity needs to be obtained from foods that also provide nutrients, instead of just 'empty calories' (these are calories derived from food containing no nutrients). Empty calorie foods include sugar; cakes, cookies, sweets, candy, soft drinks, fruit flavoured drinks that contain mostly added sugars and fatty foods.
• Protein needs increase for maintenance of existing lean body mass and the development of additional lean body mass during the adolescent growth spurt. Inadequate protein supply result in retarded growth and delay in sexual maturation.

• There is an increased amount of folate during puberty. It is needed for protein synthesis. Rich sources of dietary folate include ready to eat cereals, orange juice, bread, milk and dried beans or lentils.

• It is estimated 45% of peak bone mass is attained during adolescence, so adequate calcium intake is important for proper development of strong dense bone mass and reduction of the lifetime risk of fractures and osteoporosis. Calcium needs during adolescence are greater than they are in either childhood or adulthood because of increased demand for skeletal growth. Milk provides the greatest amount of calcium in the diet, followed by cheese, ice cream and frozen yoghurt.

• More iron is needed to help new muscle cells obtain oxygen for energy. Girls have a higher requirement than boys for iron to replace blood lost during menstruation. Vitamin C aids absorption of iron.

• Zinc is important in adolescents' diet because of its role in growth and sexual maturation.

• Take away and fast foods need to be balanced with nutrient-dense foods such as wholegrain breads and cereals, fruits, legumes, nuts, vegetables, fish and lean meats.

Adults 20-50 years

At adulthood, body growth decline. Generally, adults need food to maintain and repair the body and to keep it healthy.

In comparison to adolescents, energy requirements are lower for both men and women, as are requirements for calcium and phosphorus. There is also a reduced requirement in women for magnesium, and in men for iron. The requirements for protein and most of the vitamins and minerals remain virtually unchanged in comparison to adolescents (except for selenium in men which increases slightly).

The elderly 50+ years

The elderly is always characterised by reduced physical activity. Their energy requirements decrease gradually after the age of 50. This means that the quantity of energy food required by the aged needs to be slightly decreased. Their needs for proteins, vitamins and minerals remain virtually unchanged for both men and women. The following recommendations might be useful in ensuring a balanced diet for the elderly:

• Their diet must be dominated with foods that are nutrient dense rather than energy dense, including eggs, lean meats, fish, liver, low-fat dairy foods, nuts and seeds, legumes, fruit and vegetables, wholegrain breads and cereals and limit cakes, sweet biscuits and soft drinks. Too much fat and carbohydrates may lead to obesity and coronary heart diseases. Fat is also difficult to digest.
• If possible, the elderly must try to spend some time outside each day to boost vitamin D synthesis for healthy bones.
• Reduce the amount of sugar as it may lead to diabetes.
• Choose foods that are naturally high in fibre to encourage bowel health or prevents constipation.
• Limit the use of table salt, especially during cooking to minimize the risk of hypertension or High blood pressure.
• Calcium and phosphorus remain essential for maintenance of bones or prevent osteoporosis, blood clotting, and proper muscle functioning.
• The elderly also need vitamin C to help the body resist infections and for absorption of iron.