Energy Balance Write down FOUR factors which contribute towards a healthy diet.
How many did you get right? • Eat a variety of foods • Eat a well balanced diet • Eat five portions of fruit and vegetables a day • Exercise regularly
OBJECTIVES • Understand the different uses of energy in the body • Describe the factors affecting energy requirements. • Define the concept of a balanced diet
Food provides energy So the following can occur: • Growth • Repair • Maintenance of the body Energy is measured in Kcal or K joules
Four Types of energy • Mechanical, muscles performing basic functions. • Chemical energy is respiration, when cells release energy from food.
Chemical Energy • Chemical energy is better known as respiration. • This is when a chemical reaction allows cells to release energy from food. • Metabolic rate is the speed which this occurs.
Heat Energy • Your body takes chemicals from food you eat and turns them into energy. • Heat is generated when this breakdown occurs.
Electrical energy • This is energy used by the nervous system. • Your sense organs contain receptors. • They create electric impulses used for reflex reactions.
Daily Energy requirements = BMR + • Basic metabolic rate. • Number of calories you need to stay alive. • This can vary between people PAL • Physical level activity • Number of calories required to fuel physical activity • Dependent on the sports or activity you do
Test your understanding Can you describe what is a balanced diet using the following words? • Energy input • Energy output • Kilo calories • BMR
Different energy requirements Young old
Metabolic differences Female Male
Occupation Sedentary job Active job
Life stage Pregnancy Convalescence
Explain yourself • In pairs you need to discuss and identify three factors which affect our energy requirements. Try and include the correct terminology in your answer.
How are energy requirements measured? • DIETARY REFERENCE VALUES (DRVs) are estimated requirements on population groups. • ESTIMATED AVERAGE REQUIREMENTS(EARs) is an average estimate for a certain group of people e.g. toddlers • LOWER REFERERENCE NUTRIENT INTAKE (LRNI) is an estimate for a group of people with low energy requirements e.g. the elderly.