GCSE AQA Biology 1 Diet and Exercise

GCSE AQA Biology 1 Diet and Exercise

1. Balanced Diet

   • Diet must provide energy you need (not more)
   • Food Groups
     • Carbohydrates
       • To release energy
     • Fats
       • To keep warm and release energy
     • Protein
       • For growth, cell repair and cell replacement
     • Fibre
       • To keep everything moving smoothly through digestive system
     • Vitamins and Mineral Ions
       • To keep your skin, bones, blood and everything else generally healthy
     • Water

2. Metabolic Rate

   • Speed at which chemical reactions happen in the body
   • Affected by...
     • Gender
     • Amount of exercise
     • Genetics
     • Muscle to Fat ratio
     • Size - more cells

3. Unbalanced Diet

   • Malnutrition
     • Having too much or too little of one or more food groups (having an unbalanced diet)
   • Eating too much...
     • Obesity
       • Caused by excess carbs or fat in diet (bad diet), overeating or lack of exercise
       • Common in developed countries
       • 20% or more over max. recommended body mass
       • Health Problems
         • * Arthritis * Type 2 Diabetes * High Blood Pressure * Heart Disease * Some Cancers
         • More sat. fat increases cholesterol
         • Too much salt causes high blood pressure/heart problems
   • Eating too little
     • Particularly in developing countries
     • Health Problems
       • * Slow growth (in children) * Fatigue * Poor resistance to infection * Irregular periods (in women)
       • Deficiency Diseases
         • Caused by lack of vits and mins... * Vitamin C - Scurvy * Protein - Wasting of body tissue * Vitamin D - Rickets * Calcium - Weak bones and teeth * Iron - Anaemia * Vitamin A - Poor night vision

4. Doing exercise

   • More exercise usually = healthier
   • Increases amount of energy used and decreases amount stored as fat
   • Builds muscle - boosts metabolic rate
   • Can still be malnourised

5. Inherited Factors

   • May inherit underactive thyroid gland
     • Can lower metabolic rate and cause obesity
   • High cholesterol
     • Cholesterol is a fatty substance needed for good heath. Some inherited factors can increase its levels.

6. Evaluating Diets

   • Large survey can tell if diet is effective
   • To lose weight...
     • ...take in less energy than you use
       • Eat less fat or carbs and do more exercise