Physiology

Question 1

• understand the concept of energy intake and energy expenditure

Answer 1

20% efficiency. Genetic variability responsible for a lot of the difference.
BMR 1500-2000kcal/day
If energy intake exceeds expenditure (Sleeping metabolic rate+arousal= Basal metabolic rate, thermogenic effect of food- influenced by food type and activity level, activity), will gain weight.

Question 2

• understand the concept of body weight regulation

Answer 2

Body weight is a regulated variable, thus it is difficult to keep off weight lost- the body produces increased Grelin, even 62wks after the wt loss.
Body compensates in terms of energy expenditure to counteract changes in weight away from the set point.
The set point may have increased in modern times.

Question 3

• know the key hormones involved in energy intake

Answer 3

Gherkin released from the stomach creates hunger.
Leptin, a lipokine, released from fat (more with increased fat mass), inhibits hunger/decreases intake. It’s deficiency can be corrected but not a magic bullet for obesity rx as get leptin resistance.
Metabolic hormones: adrenaline, thyroid hormones.

Question 4

• have an understanding of the causes of obesity

Answer 4

Energy excess with physical inactivity, on a back ground of genetic susceptibility.
Also factors influencing sedentary lifestyle (increases hazard risk with time sitting, even if exercise regularly), increased portion sizes.
Physical activity influenced by individual, interpersonal, environmental, regional/national policy, global factors.

Question 5

• have an understanding of disorders of underweight particularly anorexia nervosa
know the medical conditions that are associated with involuntary weight loss

Answer 5

See themselves as being fat so restrict calories, emesis, overexercise.
(not really covered)

Question 6

How can energy expenditure be measured?

Answer 6

Doubly labelled water 
Oxygen consumption (VO2) 
Heart rate-based estimation of VO2 
Activity monitors 
Population-based algorithms

Question 7

What are the main determinants of energy expenditure?

Answer 7

Adrenaline, thyroid hormones 
Muscle mass and oxidative capacity Exercise/physical activity levels 
Non-exercise activity thermogenesis 
Shivering thermogenesis 
Brown fat?

Question 8

What is the largest determinant of 24 hour energy expenditure?

Answer 8

Fat free mass (mostly skeletal muscle)
Fidgeting
Activity levels

Question 9

Brown fat characteristics/activation

Answer 9

More mitochondria, skel m like
Higher expression of mitochondrial genes
More uncoupling protein (so less efficient ATP generation)

Question 10

What are the ecological model determinants of physical activity?

Answer 10

Individual
Interpersonal
Environmental
Regional or national policy
Global

Question 11

m

Answer 11

m

Question 12

b

Answer 12

b

Question 13

Leptin action/deficiency

Answer 13

n

Question 14

Grelin reaction to low calorie diet

Answer 14

increased

Question 15

What is the correlation between sedentary lifestyle and death?

Answer 15

Increases with time sitting, even if adhering to 30mins/day activity

Question 16

What can be used to treat obesity?

Answer 16

Increased physical activity
Reduced energy intake, caloric restriction
Pharmacological – appetite suppressants, absorption inhibitors, “metabolic activators”
Bariatric surgery