Fitness and Health

1
Fitness and Health

• Human body evolved under very different
  conditions
• Obtaining necessary calories and nutrients was a
  daily struggle
• Lots of physical exercise and exertion
• Also more disease and physical stress

2
Present Day Challenges

• Stay physically fit through exercise
• Find time to exercise
• Get correct balance of nutrients
• Type of nutrients (fat vs carbohydrates)
  important as well as total number of calories
• Food Calorie 1 kcal 4184 Joules

3
Harvard Food Pyramid

• http//www.hsph.harvard.edu/nutritionsource/pyrami
  ds.html
• Asian countries eat more carbohydrates same or
  more calories, but less fat
• Relatively fewer obese people in China and Japan
• So decreased fat intake is a good idea

4
Athletes

• Need more calories because they expend more
  energy
• Fundamentally a conservation of energy issue

5
Cholesterol

• Body must have some cholesterol
• Cannot function without some of this steroid
  related nutrient
• Problem is too high blood cholesterol
• Diet related - but cannot eliminate cholesterol
  from diet

6
Diet Issues

• Lots of involved
• Lots of politics involved
• Difficult to do long term studies under suitably
  controlled conditions
• If lots of and politics are involved, can be
  difficult to get objective scientific information
• However, it is possible

7
Diets

• Lots of ways to lose weight
• Key issue is what you are losing
• Want to lose fat
• Can lose water, glycogen (glucose polymer)
• Need to change energy balance
• Less food, more exercise - conservation of energy

8
Quick diets

• Diuretic causes water loss - but not permanent
• Restricting too much of one nutrient can be
  dangerous
• Can lose muscle which is then replaced by fat
  when you gain weight back
• Low carbohydrate causes loss of glycogen and
  associated water- but not permanent
• Slow loss through diet and exercise best way
• More extreme medical measures are sometimes taken

9
Smoking

• Carbon monoxide, nicotine, tar, and many other
  toxic or carcinogenic chemicals
• Major risk is stroke or heart attack
• Second hand smoke is also deleterious

10
Muscles

• Well known training effect
• Cell energy for short term use is stored in ATP
  (adenosine triphosphate)
• Longer term energy from glycogen starch
• Glycogen pyruvic acid
• pyruvic acidO2CO2H2O
• No O2 then pyruvic acid breaks down to lactic
  acid (causes muscle fatigue/pain)
• Exercise enhances oxygen transport