ENERGY - CCEA - AS 2 NOTES

  • Created by: sarahj123
  • Created on: 17-04-19 18:28

Energy

Needed for :

  • internal functions
  • external functions
  • growth & repair
  • maintenance
1 of 6

Calories

Water = facilitates chemical reactions that make energy from food

Calories vs Joules

Energy can be measured in : Kcal / C / J

Labels on food must have energy value given in both Kcal and KJ

1 Kcal = 4.184 KJ

2 of 6

Energy Balance

ENERGY BALANCE = Intake = Expenditure ( ratio of input to output )

Intake = Energy in = Food & Drink

Expenditure = Energy out = Exercise

Eat more = Store excess kcal as fat  ( input > output )

Eat less = Use excess fat during exercise ( output < input )

Healthy weight = Balance output & input 

3 of 6

Appetite

Appetite & Satiety center  ( nerve & chemical stimulation )

No exercise = Mechanism controlling input & output = less accurate = upset input & output = ENERGY IMBALANCE

4 of 6

Energy Imbalance

+ ve      

Input > Output

  • Excess fat accumulated ( Overweight )
  • Large portion  + Ignore true appetite

______________________________________

-ve

Input < Output

  • Fat stored used ( Weight loss )
  • Fatty tissue depleted
5 of 6

Why we need energy

Intake = Amount of energy absorbed through food intake

  • BMR = Basal Metabolic Rate = Energy burnt when the body is at rest ( needed for proper functioning of organs )

What can affect the BMR:

  • Body size = Big body needs more energy ( female = less lean tissue & more fat = lower BMR / male = more musscle - most metabolic tissue = ^ BMR - need more energy )
  • Age ( Children = ^ BMR = small body / Adults = muscle deter - lower BMR )
  • Thyroid = Secrete iodine into blood ( Thyroxin controls BMR - ^ BMR = overactive - underweight )
  • Thermogenic effect = ^ BMR after food ( body create heat = help digest )
  • Activity = oxygen uptake
  • Growth = growing tissues and cells
  • Mental energy = brain needs energy = support & protect brain cells ( stress drains energy )
6 of 6

Comments

No comments have yet been made

Similar Home Economics: Food & Nutrition resources:

See all Home Economics: Food & Nutrition resources »See all Energy resources »