1. Energy
© PDST Home Economics.

2. 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

3. Measuring Energy
Energy is measured in kilocalories (kcal) or kilojoules (kJ)
Nutrient
Kcal/kJ
Protein
Carbohydrate
Fat
Alcohol
4kcal/17kJ
9kcal/37kJ
7kcal/29kJ

4. Factors affecting energy requirements
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)
Size & Body Weight
The larger the body, the more energy it needs
Gender
Men have a higher proportion of muscle to fat compared to women, therefore men require more energy
Level of Activity
The more people active are, the more energy they need. Running requires more energy than playing a computer game

5. Factors affecting energy requirements
Occupation
Sedentary work eg. Office work, requires less energy than manual work eg. Construction cork
Climate
More energy is needed in colder climates to maintain a consistent body temperature
Pregnancy
During pregnancy & lactation, women require more energy
Pregnancy: Energy needed for the developing foetus
Lactation: Energy needed for the production of breast milk
Illness
During times of illness, different amounts of energy are required, eg, less energy is needed during convalescence
Kate Hehir

6. Role of Energy in the Body
Energy fulfils four main roles in the body
Growth
Physical Activity
Generating Heat
Basal Metabolic Rate

7. Role of Energy in the Body cont.....
Growth
Energy is also required for growing by toddlers,
young children, adolescents & pregnant women
Physical activity
Energy is required for all physical tasks, including standing, walking and running
The more strenuous the physical activity, the more energy required

8. Generating heat
To maintain the body temperature at 37˚C, energy is required
This is known as thermogenesis
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

9. 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

10. Healthy Eating Guidelines
Formulation of Guidelines – How?
Textbook Reference
Refer to the 10 healthy eating guidelines in your text book
Dietary practices of population are surveyed
The findings are analysed by nutritional experts
Areas that require attention are highlighted and considered in drawing up the list of guidelines

11. Current Healthy Guidelines
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
Food Pyramid
Refer to Diagram in your text book

12. 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:
Interpret food consumption records
Evaluate the adequacy of food supplies in meeting national nutritional needs
Design nutritional information labels
Develop new products in industry
Provide nutritional information on labels

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. Dietary Requirements of Adults
Special Considerations
Smoking & alcohol both inrease the risk of CHD
Reduce salt intake to prevent high blood pressure

21. 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

22. 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.

23. 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

24. 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

25. 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 sources
to 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

26. 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