We Need Energy for:  Basal Metabolism BMR = Basal Metabolic Rate  Physical Activity  Metabolizing Food

2. ENERGY
Energy:
 The capacity to do work, such as moving or heating
something
 Ablitiy to do work
 The food we eat gives the body energy
 Food is the fuel for the body

3. HOW TO GENERATE ENERGY
Energy In and Energy Out
Input = Food and Calories
Output = Metabolism (BMR) and Physical Activity
Energy Balance
• Weight Maintenance
• Weight Increase
• Weight Loss

4. Energy provide
 Carbohydrate Yes
 -Protein Yes
 -Fat Yes
 -Vitamins No
 -Minerals No
 -Water No
CHO protien anf fats are the energy yielding nutrients

5. ENERGY UNITS
• Energy is measured in calories or joules
• The SI unit of energy and work is the joule (J)
Defination:
We usually refer to kilojoules (1000 joules)The Joule is a very small
amount of energy

6. CALORIE
• A calorie is the amount of energy needed to raise the temperature of
1 gram of water by 1 degree celsius
• A kilocalorie is the amount of heat energy it takes to
raise a litre of water by 1ºC
• We usually refer to kilocalories
1 cal = 4.184 J (exact)

7. Calorie
A new unit was introduced as the nutritional calorie or Calorie (Cal) which is
1000 calorie units, 1 kcal
 1 Cal = 1 kcal = 1000 cal
These equalities can also be written in terms of joules.
 1 Cal = 4.184 kJ = 4184 J

8. Energy Value of Nutrients
1g Protein = 4 kilocalories or 17 kilojoules of energy
1g Carbohydrate = 4 kilocalories or 17 kilojoules of energy
1g Fats = 9 kilocalories or 38 kilojoules of energy

11. • Calorie value of carbohydrate, fat, and protein…
If you know the number of grams of carbohydrate, fat, and protein in
a food, you can calculate the number of calories in it.
• For example
A deluxe fast-food hamburger contains about 45 grams of
carbohydrate, 39 grams of fat and 27 grams of protein (see above).
• The percentage of your total energy intake from carbohydrate, fat,
and protein can then be determined by dividing the number of
calories from each energy nutrient by the total calories, and then
multiplying the result by 100.

12. Getting energy from food
 Energy is got from food in a process called cellular respiration (oxidation).
 Digested food and oxygen go into the body cells and react together to
produce energy
 Food + Oxygen → Energy + water + CO2
 Food labels tell us how much energy 100g of a food will give us

13. Energy Content of Food
• All foods give us energy.
Some food will give more energy than others it depends on the kind of nutrients in the food.
Protein, Fats and Carbohydrates give a lot of energy
 But Water, Minerals and Vitamins give very little
 100g Cabbage = 22 kilocalories
100g Cheddar cheese = 412 kilocalories
 Fats give the most energy

14. • We Need Energy for:
• Basal Metabolism
• BMR = Basal Metabolic Rate
• Physical Activity
• Metabolizing Food