Keeping healthy


Why do we need food?

We need food for energy- movement, growth etc

Unhealthy choices:

  • Not eating enough fruit & veg- Unbalanced diet, Not enough vitamins
  • Not drinking enough water- Become dehydrated, Frequent headaches
  • Eating too much fatty food- Overweight, Unbalanced diet, Risk of heart diease/ strokes
  • Not excerising enough- Overweight, Heart problems, Poor digestion
  • Not eating enough- Lack of energy, Malnutrition, Deficiency dieases

Metabolic rate: The rate of the chemical reactions that happen inside cells. This is affected by:

  • Proportion of muscle to fat
  • Amount of exercise/ activity
  • Inherited characteristics

People who exercise regulary need more food because they need more energy. When you exercise, muscle builds up, meaning your metabolism is faster. Exercisng uses up energy, meaning you need more (energy) to carry out basic needs

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How is Exercise Beneficial?

BMI = Mass / height

This gives an INDICATION of whethe you are underweight or overweight for your height.

Obesity: When someone is has a large amount of body fat, or is ove the healthy weight range for their height. This can lead to:

  • Diabetes
  • Strokes / Heart problems
  • Excess cholesterol


  • You cannot get enough food to feed your body
  • You dont have enought energy, can become underwight, develop deficiency diseases etc. Females may not get periods
  • Anorexia has the same symptoms as starvation
  • People can develop anorexia by wanting to lose weight by extreme dieting and eventually, not mentally be [able] to eat.
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What Affects how much Energy you Need?


  • People that are growing (Children and teenagers) need more energy to grow


  • Males usually have a higher muscle to fat ratio so need more energy

Amount of exercise:

  • More exercise means that you use up more energy 
  • More exercise can lead to more muscle ( higher muscle to fat ratio)


  • The mother is feeding for 2 people
  • The baby is rapidly growing


  • If you are too hot / cold, you need more energy to stay the right temperature
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Deficiency diseases


  • Lack of vitamin D- sunlight, eggs, fish etc
  • Vitamin D controls amount of calcium in bones


  • Lack of vitamin C- citrus fruits
  • Vitamin C makes collagen, a protein in blood


  • Iron deficiency- red meat, nuts, leafy veg etc
  • Lack of hemoglobin- pale skin, no energy
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Infectious Diseases

Viruses: Measles, Mumps, Chicken pox etc

Bacteria: TB, Salmonella etc

Fungi: Athlete's foot, Ringworm etc

Bacterial infection:                                                               Virus infection:

                                                   Pathogens enter the body

  • Bacteria rapidy reproduce ( Binary fission)                       Viruses insert their DNA into a host                                                                                     cell's DNA
  • Bacteria produce toxins, which make you ill                    The host cell makes more copies of                                                                                     the virus
  •                                                                                     The new viruses burst out of the                                                                                           host cell, killing it

                          The toxins/ dead cells & immune system cause symptoms

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Ignaz Semmelweis // Pathogens

  • Hungarian physician, 1818-1865
  • Showed that hand washing could reduce the amount mothers dying of childbirth (and other patients)
  • Enforced strict hand washing rules & drastically reduced the number of dying patients


How do pathogens invade our bodies?

  • Mouth- food
  • Ears- droplets
  • Cuts/ wounds & infections- bacteria
  • Animal bites
  • Direct contact- sex
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Treating Diseases & Problems

Antibiotics kill bacteria

Painkillers only treat the symptoms

Side effects of vaccines:

  • A study was released saying that the MMR vaccine would give your child autism
  • A large percentage of parents didnt get their child/ren vaccinated
  • When the disease went round, many children got ill and some were close to dying
  • Eventually, other research showed that the first study was biased and untrue

Epidemics/ Pandemics:

  • People from all over the world travel to other countries around the world
  • Some people may catch a disease from a country and spread the disease when they go to another country
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Antibiotic Resistance

  • When you catch a bacterial disease, a few of the bacteria might mutate, making them resistant to an antibiotic.
  • When the antibiotic is given, the mutated bacteria still survive & can breed & multiply.
  • The new mutated bacteria is resistant


  • This is a disease that is resistant to most antibiotics
  • It only affects very ill people
  • Causes big problems in hospitals
  • It has become resistant by being surrounded by many types of antibiotic all the time
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