Metabolism

1
Metabolism
2
Feasting

• Feasting adds to body stores of carbohydrate and
  fat
• Excess carbohydrate ? used to fill glycogen
  stores ? excess glucose stored as fat
• Excess fat ? stored as fat
• Excess protein ? remove N and store as fat

3
Fasting Glycogen Available

• Draw upon stores during fasts (even short-term)
  and during exercise
• Liver glycogen ? blood glucose ? energy for all
  cells
• Muscle glycogen ? muscle glucose ? energy for
  muscle cells

4
Fasting Glycogen Available

• Draw upon stores during fasts (even short-term)
  and during exercise
• Fat stores ? fatty acids in blood ? provide
  energy for all cells, but brain and CNS

5
Fasting Glycogen Stores EMPTY

• Only protein and fats are available as a source
  of energy
• See board!

6
Estimating Energy Needs

• Body uses energy for
• Basal metabolism
• Thermic effect of food
• Physical activity

7
Basal Metabolism

• Basal metabolism
• Energy needed to maintain the body at complete
  rest (physical, emotional, and digestive)
• Largest component of daily energy expenditure

8
Basal Metabolism

• Basal Metabolic Rate (BMR)
• kcal burned per hour per kg body weight

9
Basal Metabolism

• BMR impacted by
• Lean body mass
• More LBM, the higher your BMR
• More fat, the lower your BMR
• Age and gender (related to LBM)
• BMR slows with age
• BMR higher in males

10
Basal Metabolism

• Height
• Taller, thinner people have a higher BMR
• More surface area to support
• Fever raise BMR
• 10 F fever raises BMR by 7
• Fasting and malnutrition lower BMR

11
Basal Metabolism

• Smoking and caffeine raise BMR
• Stress raises BMR

12
Thermic Effect of Food

• TEF energy needed to digest, absorb, transport,
  and metabolize nutrients
• Smallest component of daily energy expenditure
• 10 caloric intake

13
Physical Activity

• Physical Activity energy needed to support
  voluntary activity
• Energy required impacted by
• Muscle mass
• Body weight
• Nature of activity
• Duration, intensity, frequency

14
Energy Expenditure

• Summary
• To maintain energy balance, energy input must
  balance energy expenditure
• Expend energy to
• support basal metabolism
• process foods (TEF)
• support physical activity