This presentation contains everything you need to know in healthy eating if your doing biology AQA GCSE.

1. Healthy diets
Biology - Topic 2- IGSCE

2. Nutrients
For a healthy diet you need:
 Carbohydrates- pasta
They give you energy
 Proteins- Fish
Growth and replacement of dead cells
 Fats- Butter
Energy store and cell membranes
 Vitamins and Minerals- fruit/ vegetables/ vitamin D/ Calcium
Needed in small amounts for bone functioning e.g. vitamin D for
healthy bones
 Water
Needed for chemical reactions
 Fibre- brown bread
Bulks food to ease movement through intestine. Prevents
constipation

3. Malnutrition and deficiencies
You only need a small amount of vitamins and minerals
but without them you will suffer a deficiency
 Deficiency- means a ‘lack of’. If your diet is not balanced
e.g. too much or too little of fat and you will become
malnourished.
e.g. Calcium deficiency leads to brittle bones.
Vitamin C deficiency leads to bleeding gums
called scurvy
 Malnourished- means you have too much or too little
nutrients
e.g. An anorexic person will eat very little:. Are
malnourished
An obese person is severely overweight and so
may eat too much :. Are Malnourished

4. Weight Problems
 BMI- (Body mass index) This calculation is used as a guide to find
out if a person is obese or under weight. However there are
sometimes problems with using BMI. For example a body builder
has a lot of muscle and muscle weighs a lot, they would
therefore have an obese BMI but not have a lot of fat. Other
problems could be thing like: Male/Female, ethnic group and
metabolic rate.
 Obesity- Obese people have too much mass and often its fat.
The problems of being obese
 Arthritis(worn joints)- the knee joint are worn due to the high mass
straining them
 Diabetes(Blood sugar levels)- the mass prevents the body from
controlling blood sugar levels.
 High Blood pressure+ heart disease- the high mass strains the
heart muscle as the body works higher to move the mass. Fatty
diets can cause blood vessels to narrow and increase blood
pressure.

5. BMI Calculation and
metabolic rates
Body mass
index(BMI) =
Metabolism – Metabolism if the rate at which
you burn off calories. People who have a high
metabolic rate have a lot of muscle and
exercise a lot.

6. Weight problems
 Obesity, anorexia and Vitamin deficiencies are effects of malnutrition.
 Children are effected more when there is a food shortage as they need
more food for growth
 It is difficult to collect accurate data on Malnutrition as normally in poor
counties there is bad healthcare and that is where it occurs the most.
 It is difficult to collect accurate data on obesity as some obese people
may not visit the doctors regarding their weight problem.
 The most common cause of obesity in developed countries is that are
over eating or don’t know the risks of obesity.
 A study based on questionnaire's may not be correct as some people
are lying about their weight as they are conscious of their weight.
 Heart disease, arthritis, high blood pressure and diabetes are health
problems linked to obesity.
 High levels of obesity can cause economic problems in the UK as
money would be spent on heart disease treatments and Arthritis
treatments.

7. Energy Content
Method:
 Measure 20cm³ of water into a boiling tube.
 Record the temperature of the water
 Weigh a small amount of the snack food and record its
mass.
 Put the food onto a mounted needle and light it. Once
it is alight put it under the boiling tube of water.
 when the food has completely burnt out, record the
new temperature of the water.
To find the energy given out by food:
Energy(joules)= 20 x 4.2 x temperature rise of water
To find the energy content in the food:
Energy content of food=

8. Cholesterol
Cholesterol is a fatty substance that circulates the blood. There are 2 types of
cholesterol:
 Good cholesterol called- HDL
 Bad cholesterol called- LDL
LDL deposits in the inside walls of the arteries and narrows the artery.
Cholesterol cannot be removed once deposited but floating(in the blood)
cholesterol can be removed over time by HDS’s
Arteries supply blood to the organs, this means if an artery bursts from high
blood pressure or becomes too narrow organs like the heart will lack oxygen
and start to die. If this happens to your heart it is called a heart attack. This
mainly happens when the coronary artery blocks. An angioplasty needs to be
done. This is when a balloon is put into the artery and blown up to squash the
cholesterol down, sometimes a stent is put in too. A stent is like a metal spring
used to keep the artery wide. A stroke can also happen too, this is when a
collection of red blood cells form a blood clot in a capillary in the brain, so part
of the brain tissue dies. You will often become paralysed if you have had a
stroke. The amount of Cholesterol produced by your liver is often effected by
your genes.

9. Statins and Sliming diets
Good points on Statins:
 It lowers the amount of cholesterol by stopping the liver
making so much cholesterol.
 Reduces the chance of stroke and Heart Attack by 25%-
40%
 It helps reduce cholesterol along side a change in diet
Bad points on Statins:
 Can cause liver damage in some people
 Patients may think that they can continue an unhealthy
diet. So it does not make people live a healthy lifestyle.
Conclusion:
Statins are only good if the patient has taken the statin and
made a change in their diet.
Slimming diets restrict Calories so you take in little energy

10. Key Words
 carbohydrate
 Protein
 Fats
 Vitamins
 Minerals
 Fibre
 Energy
 Malnourished
 Deficiency disease
 Metabolism
 Metabolic rate
 Obesity
 Starvation
 Cholesterol
 Statins
 Slimming diet