Energy needs

• What is the definition of kilocalorie (kcal)/kilojoule (kJ)?


  Units used to measure energyUnits used to measure energy
• Functions of energy in the body


  Energy is vital for life. We get our energy from the foods we eat and then use it all the time in the body for different jobs, for example to:

  . Allow the body to grow and develop

  . Move muscles and be physically active

  . Produce heat to keep the body warm

  . Produce sound when talking, singing, shouting

  . Send messages from the brain to make the nerves work

  . Make chemical reactions take place in cells, the digestive system, the brain, etc.
• Main sources of energy in the diet


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

  1kcal = 4.2kJ
• What is the primary source of energy for the body?

  Carbohydrate
• How much energy does 1g of pure carbohydrate provide?

  1. 75 kcal or 16 kJ
• What are the main sources of carbohydrates?

  • Foods containing sugars and starch (e.g., fruits and vegetables)
  • Cereals (e.g., rice, wheat, maize, barley)
  • Cereal products (e.g., cakes, biscuits, breads, pasta, pastries)
  • Honey and syrups
  • Sugar used in cooking
• Why is carbohydrate considered the main source of energy for the body?

  Because it is broken down into glucose, which provides energy.
• Where is some glucose stored in the body?

  In the liver and muscles as glycogen
• How does the body use glucose from carbohydrates?

  The body breaks down carbohydrates to use the glucose for energy.
• What happens to excess carbohydrates that are not used for energy?

  They are converted into fat and stored in the body.
• Why do sugary drinks contribute to fat storage in the body?

  Because excess sugars are easily converted into fat.
• What is the process of carbohydrate metabolism in the body?

  1. Carbohydrates are consumed.
  2. The body breaks them down into glucose.
  3. Glucose is used for energy.
  4. Excess glucose is stored as glycogen.
  5. Any remaining excess is converted into fat.
• What is the primary source of energy mentioned in the study material?

  Fat
• How much energy does 1g of pure fat provide?

  9 kcal or 37 kJ
• What are the main sources of visible fats and oils?

  • Butter
  • Lard
  • Vegetable fat spread
  • Cooking oil
  • Suet
  • Ghee
  • Fat on meat
  • Oily fish
• What are examples of foods containing invisible fats and oils?

  • Cakes
  • Pastries
  • Fried foods and snacks
  • Biscuits
  • Chocolate
  • Meat products (e.g., sausages, burgers)
  • Ice cream
  • Cheesecakes
  • Cheese
  • Cream
  • Avocados
  • Coconut
  • Seeds
  • Nuts
  • Some fast foods and ready meals
• Do fats and oils have different energy values?

  No, they have the same energy values.
• Where is fat that is not used for energy stored in the body?

  In special cells in adipose tissue under the skin or elsewhere in the body.
• How is fat converted into energy?

  Fat is converted into glucose and used for energy.
• When is fat used for energy in the body?

  When the diet does not have enough carbohydrates.
• What is the process of using fat for energy when carbohydrates are insufficient?

  Fat is converted into glucose for energy, which is a slow process.
• Source of energy: Protein


  Energy value - 1g of pure protein gives 4kcal/16kJ

  Main sources - meat, poultry, fish, shellfish, eggs, milk, dairy foods (e.g. cheese, yogurt, quark, fromage frais), soya beans, quinoa, lentils, peas, beans, cereals (e.g. wheat, rice, oats, barley, rye, millet), nuts, seeds, gelatine

  . The body will only use protein if there is not enough carbohydrate or fat in the diet or the body’s stores of energy have been used up.
• Source of energy: Alcohol


  Energy value - 1g of pure alcohol gives 7kcal/29kJ

  Main sources - many people drink alcohol in drinks such as beers, wines and spirits (vodka, whiskey etc.)

  . Drinking alcohol regularly can significantly contribute to energy intake and, if the energy it provides is not used up, it will be converted to fat and stored in the body.
• Foods that contain a high proportion of fat and carbohydrate (especially sugars) are said to be energy dense (e.g. pastries, chocolate bars, cakes, biscuits, meat products such as sausages, pies, pizzas.)
• Effects of a deficiency of energy in the diet


  The body needs a supply of energy every day

  . The body loses weight - if there is not enough energy in the diet to meet the needs of the body, the energy stored in body fat will be used. This will gradually reduce fat stores.
• Effects of an excess of energy in the diet

  Energy from food that is not used up by the body each day will be stored in body fat cells in case it is needed in the future. If this happens on a regular basis, the weight of the body will gradually increase.
• Amount of energy needed every day for different life stages


  The amount of energy we need from food depends on the amount of energy we use every day. This is influenced by three things:

  1. Our Basal Metabolic Rate (BMR)

  2. Our Physical Activity Level (PAL)

  3. Our life stage - e.g. children need extra energy for growth; extra energy is needed during pregnancy, or to breastfeed a baby.
• What is the definition of energy dense?


  A food that contains a lot of fat and/or carbohydrate and has a high energy value.
• What is the definition of BMR?

  Basal Metabolic Rate is the amount of energy we need to keep our body alive.
• What is the definition of PAL?


  This means Physical Activity Level, and is the amount of energy we use for movement and physical activity every day.
• What is the definition of energy balance?


  The amount of energy we get from food each day is the same as the amount of energy we use each day.
• What is the Basal Metabolic Rate (BMR)?

  The amount of energy needed by the body just to stay alive
• Why is BMR important for the body?

  It keeps the heart beating, lungs breathing, and brain functioning
• What percentage of daily energy requirements is typically used for BMR?

  40-70%
• How does age affect BMR?

  Children have lower rates than adults, and BMR decreases in old age
• How does body size influence BMR?

  As body size increases, BMR increases due to higher energy needs
• Why do women generally have a lower BMR than men?

  Women tend to be smaller and have less lean tissue and more body fat
• What type of tissue uses more energy, lean tissue or fat?

  Lean tissue
• How can physical activity level (PAL) affect BMR?

  Regular exercise can raise BMR levels
• What factors influence BMR?

  • Age: lower in children and decreases in old age
  • Body size: increases with larger body size
  • Gender: women generally have lower BMR than men
  • Physical Activity Level (PAL): regular exercise can raise BMR