BIOC Lecture 5: Fasting

Question 1

What are by far the greatest proportion of our stores?

Answer 1

Fats

Question 2

What is the problem with using proteins as an energy store?

Answer 2

Their main roles are impaired

Question 3

What is the compensation for falling glucose levels during long term starvation?

Answer 3

Ketone bodies and an increase in fatty acids in the blood and a further shifting of tissues from using glucose to using fatty acids

Question 4

Where do ketone bodies come from?

Answer 4

Fat/fatty acids

Question 5

What happens to metabolic fuels after 12 hours starvation?

Answer 5

Approximately same coming from glucose and fat (41% + 46%), small amount from protein (13%)

Question 6

What happens to metabolic fuels after 60 hours starvation?

Answer 6

Using less glucose (6%), prominently fat (75%) and increased protein (19%)

Question 7

What are metabolic fuels?

Answer 7

Glucose, fat, protein

Question 8

What are plasma fuels?

Answer 8

Ketone bodies, glucose, fatty acids

Question 9

What happens to plasma fatty acids during long term starvation?

Answer 9

Small increase

Question 10

What happens to plasma glucose during long term starvation?

Answer 10

Small decrease but bigger proportionally to fatty acids increase

Question 11

What happens to ketone bodies during long term starvation?

Answer 11

HUGE increase

Question 12

Are fatty acids good transport molecules?

Answer 12

NO

Question 13

Are ketone bodies good transport molecules?

Answer 13

YES

Question 14

What is the biggest store of fuel?

Answer 14

Fat (15kg)

Question 15

What is the next biggest store of fuel?

Answer 15

Protein (6kg) - it has roles so we don’t want to get rid of it

Question 16

What is the smallest store of fuel?

Answer 16

Glycogen (0.2kg)

Question 17

What is the order of prominence of circulating fuels from most to least?

Answer 17

Glucose, TAGs, FFA’s

Question 18

What happens to brain mass after long term starvation?

Answer 18

Very little change (7% loss)

Question 19

What happens to the lung and liver mass after long term starvation?

Answer 19

Moderate/high loss (30%)

Question 20

What happens to the heart and muscle mass after long term starvation?

Answer 20

High loss (40%)

Question 21

What happens to kidney and pancreas mass after long term starvation?

Answer 21

High loss (50%)

Question 22

What is the order of priority from high to low in organs that are maintained during starvation?

Answer 22

Brain, Liver, Lungs, Heart, Muscle, Kidney, Pancreas

Question 23

Where does glucose come from during long term starvation?

Answer 23

From protein, ketone bodies spare glucose

Question 24

What are other body effects from long term starvation?

Answer 24

Reduced metabolic rate, change in thyroid hormones

Question 25

What causes death from starvation?

Answer 25

• Loss of organ function
• Decrease in immune system
• Cardiac failure

Question 26

What is whole body calorimetry?

Answer 26

Measures temperature and CO2 produced - measuring how much energy someone is expending

Question 27

Dietary intakes typically vary more than what?

Answer 27

Weight

Question 28

An extra 15g of sugar a day correlates to the gain of what?

Answer 28

About 2.5kg of fat per year

Question 29

What is there considerable evidence towards?

Answer 29

That each person has a set point

Question 30

What does RMR vary between, and what is the mean?

Answer 30

4.3MJ/d to 10.5MJ/d, mean of 6.3MJ/d

Question 31

What accounts for differences in RMR?

Answer 31

Differences in lean mass mostly aswell as fat mass and age

Question 32

RMR of the same lean mass can vary up to?

Answer 32

32%

Question 33

Metabolic rate declines with…

Answer 33

Age

Question 34

What is lean mass associated with?

Answer 34

Protein - higher muscle = higher RMR