Biology Diet and Food

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  • Created by: Henna
  • Created on: 14-01-13 17:51

Biology Diet and Food

   

 We need to have a BALANCED DIET to get enough NUTRIENTS which, provide us with energy.      

 Nutrition allows us to make ENERGY, GROW and REPAIR.

Benefits of a BALANCED DIET:

  • Better health
  • Stronger immune system
  • Ill less often
  • Learn better
  • Stronger 
  • More productive 

Carbohydrates = main source of ENERGY (pasta, rice, breads)

Fats = energy, cell membranes, water proofing, fat soluble vitamin absorption (cakes, crips)

Vitamins = some water soluble others fat soluble (B3 B6)

Proteins = source of AMINO ACIDS for cell repair and growth (1st class - meat) (eggs, fish) 

Minerals = INORGANIC essential for normal function (calcium, iron)

Water = Transport around the body and 60% of the body is made up of water

Fiber or Roughage = INDIGESTIBLE needed to keep the digestive system healthy, helps move food through the gut. (bran, wholemeal bread)

Different people need different amounts of food.

57% = CARBOHYDRATES = bread, pasta, wheat, potatoes 

30% = FATS = cakes, sweets, butter

13% PROTEINS = 1st class = Meat, fish

Weight gain occurs when a person eats more food energy than needed to live

The energy that is not needed is DISPOSITED as FAT in the ADIPOSE TISSUES 

Obesity

Form of malnutrition = unbalanced diet (too much energy)

BMI

BMI = Body mass index 

It can be calculated by:

mass/height (metres^2)

  • less than 18.25 = underweight
  • 18.25 - 25 = average weight
  • 25 - 30 = overweight
  • 30 - 35 = obese class 1
  • 35 - 40 = obese class 2
  • 40+ = obese class 3

A growing problem of Obesity 

  • - 1980 = 6% men 8% women 
  • - 2000 = 25% men 20% women
  • - 1995 - 2004 boys & girls (children 11-15)

15% - 26% = girls

14% - 24% = boys

Reasons for increase

  • Availability of food
  • Cheaper food
  • Less exercise
  • Bad parenting 
  • Availability in markets

Health risks caused by obesity

  • - 3000 deaths
  • - Cancer
  • - Cardiovascular disease
  • - Type 2 diabetes linked to
  • - Gallstones
  • - Osteoarthritis
  • - Hypertension (high blood pressure)

Atherosclerosis 

This is the NARROWING and HARDENING of the coronary arteries (blood vessels supply the heart) 

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Avoiding this problem

  • Eating fibre
  • Moderate alcohol consumption
  • Eating oily fish

Salt 

  • Decreases water potential of blood
  • Water moves into blood (OSMOSIS) and pressure INCREASES
  • High blood pressure (HYPERTENSION) leads to damage in the INNER LINING of the arteries which makes way for ATHEROSCLEROSIS 

Lipids

  • Essential to diet
  • Animals = saturated 
  • plants = unsaturated
  • Saturated = harmful
  • Poly and Mono = unsaturated fats eg,Olive oil = beneficial

c-c-c-c-c-c-c-c SATURATED 

c-c-c-c-c-c=c-c UNSATURATED (contains double bond

Cholesterol 

  • is not a Triglyceride
  • found in SATURATED FATS
  • found in liver from SATURATED FATS
  • 45-47% deaths from Coronary heart diseases are linked to high cholesterol levels of 5.2mmol dm-3

Why is Cholesterol in the blood 

  • essential for good health
  • cell membranes
  • making steroid based…

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