1. Food Groups, BMI and BMR- Biology Revision Material By: Zoe Allen

2. Food Groups The different food groups all have different uses in the body. We need the right balance of food to keep us healthy. Carbohydrates release energy Fats insulate, and release energy Protein is for growth, cell repair and cell replacement Fibre is good for the digestive system Vitamins and mineral ions help keep everything generally healthy e.g. calcium- bones and teeth etc.

4. BMR We need energy to fuel the Chemical Reactions that take place within the body that allow us to move and keep us alive. The chemical reactions are called metabolism; the speed of which they occur is called metabolic rate. BMR stands for Basal Metabolic Rate.

5. BMR There are variations in peoples metabolic rates, because we are all different. Some factors effecting metabolic rate are: Proportion of fat to muscle in the body, as muscle needs more energy than fatty tissue. This means that people with a higher proportion of muscle to fat in their bodies will have a higher metabolic rate. Gender, as men have a higher proportion of muscle to women.

6. BMI BMI stands for Body Mass Index. It is an equation which tells you whether you are over weight or under weight: BMI = mass in kg ÷ (height in m)² For example: What is the BMI of a 1.7 m person with a body mass of 60 kg? BMI = 60 ÷ (1.7)² = 60 ÷ 2.89 = 20.8

7. BMI Table This table summarises the meanings of different BMI calculations. BMImeaning Under 18.5Underweight Between 18.5 and 24.9Normal Between 25.5 and 29.9Overweight Between 30 and 39.9Obese Over 40Very Obese

8. Revision Questions 1. Name all the food groups you need to eat to have a balanced diet. 2. Put these jobs in order of how much energy they would need from their food (highest to lowest) a)mechanic, b)professional runner, c)secretary? 3. What does BMR stand for? 4. What are the chemical reactions called within the body? 5. What is the BMI of a 1.4m person with a body mass of 57kg?

9. Answers! 1. Carbohydrates, fats, Proteins, Fibres, Vitamins and mineral ions. 2. Professional runner, mechanic, secretary 3. Basal Metabolic Rate 4. Metabolism 5. 57÷(1.4)²= 29.1 (Overweight)