ENERGY© PDST Home Economics.

Energy

Energy is the ability to do work The amount of energy the body needs depends

on a variety of factors, including : age, size & body weight, gender, levels of activity, occupation, climate, pregnancy, & illness

Measuring Energy

Energy is measured in kilocalories (kcal) or kilojoules (kJ)

Nutrient Kcal/kJ

ProteinCarbohydrateFatAlcohol

4kcal/17kJ4kcal/17kJ9kcal/37kJ7kcal/29kJ

Factors affecting energy requirements

1. Age

Young people require more energy as they are growing rapidly & tend

to be very active. As people get older energy requirements decrease,

together with their BMR (Basal Metabolic Rate)

2. Size & Body Weight

The larger the body, the more energy it needs

3. Gender

Men have a higher proportion of muscle to fat compared to women, therefore men require more energy

4. Level of Activity

The more people active are, the more energy they need. Running requires more energy than playing a computer game

Kate Hehir

4. Occupation

Sedentary work eg. Office work, requires less energy than manual work eg. Construction cork

5. Climate

More energy is needed in colder climates to maintain a consistent body temperature

6. Pregnancy

During pregnancy & lactation, women require more energy

Pregnancy: Energy needed for the developing foetus

Lactation: Energy needed for the production of breast milk

7. Illness

During times of illness, different amounts of energy are required, eg, less energy is needed during convalescence

Factors affecting energy requirements

Role of Energy in the Body

Energy fulfils four main roles in the body

1. Growth

2. Physical Activity

3. Generating Heat

4. Basal Metabolic Rate

Role of Energy in the Body cont.....

1. Growth

Energy is also required for growing by toddlers,

young children, adolescents & pregnant women

2. Physical activity Energy is required for all physical tasks,

including standing, walking and running The more strenuous the physical activity, the

more energy required

3. Generating heat To maintain the body temperature at 37˚C,

energy is required This is known as thermogenesis4. Basal Metabolic Rate (BMR) The minimum amount of energy needed to keep

internal organs working and to maintain body temperature

Each person’s BMR is determined by their:- Body weight- Age- Gender

BMR is measured when a person is completely at rest, twelve hours after eating

Energy Balance

Energy balance is reached when :

energy intake = energy output If energy intake is greater than energy output, this

means being overweight or obese If energy intake is less than energy output, this

means being underweight Empty kilocalories provide energy but do not

supply the body with any nutritional value, e.g. Soft drinks

Daily Energy Requirements Table: Refer to Textbook

Healthy Eating Guidelines

Refer to the 10 healthy eating guidelines in your text book

1. Dietary practices of population are surveyed

2. The findings are analysed by nutritional experts

3. Areas that require attention are highlighted and considered in drawing up the list of guidelines

Textbook Reference

Formulation of Guidelines – How?

Current Healthy Guidelines

Food Pyramid

Refer to Diagram in your text book

Function of Healthy Eating Guidelines To improve the nutritional status of the

Irish diet To promote an active & energetic lifestyle To respond to growing concerns about

childhood & adult obesity To recommend a reduction in over-

processed foods To recommend an increase in fibre to

prevent disorders of the bowel To ensure that all food groups & servings

are met

Reference Terms

RDA: Recommend Dietary Allowance

LTI: Lowest Threshold Intake: the least amount of nutrient requirements that are needed by the public

Function of RDA’s: RDA’s help to:

1. Interpret food consumption records

2. Evaluate the adequacy of food supplies in meeting national nutritional needs

3. Design nutritional information labels

4. Develop new products in industry

5. Provide nutritional information on labels

Dietary Reference Values (DRV)

Dietary Reference Terms (DRV): RNI, LRNI, EAR These comprise a series if estimates of the

amount of energy & nutrients needed by different groups of people

RNI: Reference nutrient intake LRNI: Lower reference nutrient intake EAR: Estimated average requirements

Food Composition Tables: Show the nutrient content of different foods per 100g or of liquid & they also show the energy value of foods. Refer to textbook to view Tables

Dietary Requirements of Babies

First 6 months babies are fed milk Either breast milk or formulated milk – Development & growth Breast milk contains all the nutrients a baby needs & is recognised

as being the best for babies

Advantages of Breast feeding Contains antibodies that build up the baby’s resistance to diseases Correct temperature No need to prepare bottles or buy formula, which saves on time &

eliminates cost Sterile Promotes bonding between mother & child Babies are likely to gain the correct amount of weight Easier to lose excess baby weight

Reasons for not Breast feeding:1. HIV positive 2. Use of illegal drugs 3. Use of

prescribed drugs

Weaning

Solid foods are introduced when the baby is between 4 & 6 months

Single-ingredient foods should be used(this gives time to notice any reaction – allergies/intolerances

Infant cereals, pureed fruit & vegetables are the first foods given to babies

Factors to consider when weaning No sugar or salt should be added A balanced of foods from the four major food groups is

recommended Never give babies tea or coffee Honey should also be avoided until the baby is one year old Avoid additives by using fresh homemade food

Dietary Requirements of Children

Children need a highly nutritious diet as they continue to grow & develop

Protein: This promotes growth & is found in meat, eggs & cheese Calcium & vitamin D: These help develop teeth & bones & are

found in dairy products, particularly milk & cheese Iron & Vitamin C: These promote general health & foods such as

meat & dark green vegetables are rich in these nutrients Energy: Children who are active need a high intake of energy

foods Sugary sweets & snacks should be avoided in order to reduce

the risk of obesity & tooth decay Portion sizes should be relative, i.e. For a child small portion

sizes are key. It is also important that food is arranged attractively as children, like adults, ‘eat with their eyes’

Lunches should be well balanced, e.g. Sandwiches should have varied fillings. Fruit & yoghurt should be included with a healthy drink

Dietary Requirements of Adolescents

Adolescence is a time of continual development & change

Protein: Needed for growth & is found in meat & fish Calcium & vitamin D: For healthy teeth & bones.

Found in milk & cheese Iron: Important for teenage girls as they begin

menstruation, which leads to a loss of iron from the body; this in turn can lead to anaemia. They must, therefore, ensure they include iron-rich foods in their diet. Eg. Red meat & offal

Vitamin C: Increases the absorption of iron. It is also an important factor in the diet of teenagers, girls in particular. Vitamin C is found in fresh fruit and vegetables

Energy requirements depend on the teenager’s level of activity. Very active teenagers require high-energy foods

High fibre foods are a good alternative to sugary foods

Problems associated with eating patterns of adolescents

Eating disorders, such as anorexia nervosa & bulimia nervosa

Missing meals Eating a large amount of fast food & snacks ‘Faddy’ eating High energy intake through snacks, etc. But low

intake of nutrients Start of alcohol consumption Poor diet can contribute to problems such as acne &

obesity

Dietary Requirements of Adults Protein: - repair the body’s cells, found in meat, fish & eggs Fat: Polyunsaturated fats reduce the risks of coronary heart

disease e.g. oily fish Carbohydrates: - provide energy. Reduce refined

carbohydrate & replace them with high-fibre foods, e.g. Wholegrain bread

Vitamins: Vitamin B for the release of energy from food. Vitamin C for the absorption of iron. Vitamin D for the absorption of calcium (oily fish, milk)

Minerals: Iron for healthy blood & to prevent anaemia; calcium for strong bones & healthy teeth (milk & cheese)

Water: Water is important to remain hydrated

Dietary Requirements of AdultsSpecial Considerations Smoking & alcohol both inrease the risk of CHD Reduce salt intake to prevent high blood

pressure

Dietary Requirements of Elderly

Protein: repair of body cells, found in eggs, fish Fat: Provides energy. To maintain low cholesterol & to reduce

the risk of coronary heart disease eat unsaturated fats e.g. Oily fish, polyunsaturated butter

Carbohydrates: Necessary for energy. Choose fibre rich e.g. wholegrain cereals, fruits & vegetables

Vitamins: Vitamin C(fruit & vegetables) for iron absorption & the healing of wounds. Vitamin A(liver, eggs, carrots) for healthy eyes & skin. Vitamin D(milk, yoghurt) for the absorption of calcium

Minerals: Calcium(milk, cheese) for strong bones. Iron(offal, dark green vegetables) to prevent anaemia

Water: This is necessary to remain hydrated

Dietary Requirements of Elderly

Special Considerations Sugar intake should be reduced to prevent

diabetes Salt intake should be reduced to prevent high

blood pressure Spicy foods should be avoided to prevent

indigestion Choose foods that are easily digestible, e.g.

white fish, eggs & milk.

Dietary requirements of convalescents

Protein: Repair of body cells e.g. eggs, fish Fat: Reduce saturated fat & replace with polyunsaturated

fat e.g vegetable oils Carbohydrates: Reduce as not using much energy Eat

high fibre foods to prevent constipation e.g. prunes Vitamins: Vitamin A in oily fish and liver good for healthy

skin and respiratory tract. Minerals (Calcium & iron): These are important to

promote recovery, e.g. To heal wounds & prevent anaemia. Milk, cheese, eggs, offal & dark green vegetables should be included

Water: This is important to maintain hydration, as dehydration during an illness is very common

Dietary requirements of convalescents

Special Considerations Small portions that are easy to eat are preferable Meals prepared in a hygienic environment

(because of an increased susceptibility) to illness Foods that are easy digestible, such as white

fish, eggs & milk, should constitute a sizeable portion of food intake

Pregnant & Breast feeding Women Protein: growth of new body cells Fat: Essential fatty acids (oily fish, eggs, liver) are necessary

for a foetus’s nervous system Carbohydrate: necessary for energy, choose high fibre

sourcesto prevent constipation e.g. wholemeal bread, pasta, fruit &

veg. Vitamins: Vitamin B folic acid (fortified cereals, leafy

green vegetables) necessary to prevent neural tube defects, such as spina bifida, in foetuses. Vitamin C- absorption of iron. Vitamin D- absorption of calcium

Minerals: Calcium (dairy products) for strong bones & healthy teeth. Iron for healthy blood & prevent anaemia in both mother & baby

Water: necessary for hydration

Pregnant & Breast feeding Women

Special Considerations Extra energy is needed during pregnancy, about

200 kcals Salt intake should be reduced to prevent high

blood pressure & water retention (odema) Do not smoke- low birth weight No Alcohol- can cause foetal alcohol syndrome Pregnant women should not eat raw eggs,

cooked chilled foods, soft cheese, shellfish, etc. To prevent the risk of food poisoning, such as salmonella & listeria. Can lead to miscarriage