Weight ProblemsTopic 9.7 Animal Systems

• We have looked at how different people have different energy requirements.

• But what happens if a person takes in more food than they need????

• In today’s lesson we will investigate how having too much or too little food can affect a person’s health.

• If you take in too much food (energy) then your body will store what it doesn’t need as fat.

• If you continue to take in extra food over a long period of time you will put on weight and you may become obese.

What does “obese” mean?

• To work out whether someone is obese or not we have to first take two factors into account:

• Height and weight

• Using this information we can work out a persons body mass index (BMI)

BMI

• To calculate a persons BMI we use the following formula

• BMI = Weight (Height)2

For example

• Caroline has a mass of 48 kilograms, her height is 1.5 metres.

• Caroline’s BMI = 48 = 48 =21.3

(1.5) 2 2.25

• Once we know a persons BMI we can assess whether they are healthy or not.

• A BMI value below 18.5 means the person is under weight. Above 35 the person is obese.

• Being Obese can cause lots of health problems

How can we lose weight?

• Reduce the amount of energy (food) you take in.

• Increase the amount of energy you use by doing more exercise.

• Most people do a combination of the two.

Starvation

• In some parts of the world people do not have enough to eat. This leads to starvation.

• People that are undernourished can become very thin as their muscles waste away. They also become more susceptible to disease.

Diet advise

• Choose Homer or Mr Burns and write down some diet advice for them.