2: Physiology of feeding and satiety

Question 1

What is energy homeostasis?

Answer 1

Energy intake is matched to energy expenditure

Question 2

How is excess energy stored?

Answer 2

Glycogen

Fat

Question 3

What is the result of accessible junk food plus a sedentary lifestyle

i.e intake / expenditure mismatch?

Answer 3

Obesity

Question 4

How is BMI calculated?

Answer 4

Weight (kg) / [Height (m)]²

Question 5

Which BMI ranges correspond to the classifications:

Underweight

Normal

Overweight

Obese

Morbidly obese

Answer 5

< 18.0 ⇒ Underweight

18.0 - 24.9 ⇒ Normal

25.0 - 29.9 ⇒ Overweight

30.0 - 39.9 ⇒ Obese

> 40.0 ⇒ Morbidly obese

Question 6

Levels of ___ have increased dramatically in the past 20 years.

Answer 6

obesity

Question 7

Obesity increases your chances of early ___.

Answer 7

death

Question 8

What are the two major factors influencing obesity?

Answer 8

Genetics - increases risk but not essential for disease expression

Environment - pushes people on to develop obesity

Question 9

What is an endocrine condition associated with obesity?

Answer 9

Type 2 diabetes mellitus

Question 10

What are some cardiovascular conditions associated with obesity?

Answer 10

Hypertension

MI

Stroke

Question 11

During which situation is the energy stored by fat used?

Answer 11

Starvation

Infection (where you don’t feel like eating)

Question 12

Increased body fat alters ___ function.

Answer 12

brain

Question 13

Where is information regarding energy intake integrated?

Answer 13

Hypothalamus

Question 14

What is satiation?

Answer 14

The feeling of “fullness” after a meal

Question 15

What is satiety?

Answer 15

The period of time between one meal and the next

Question 16

What are satiation signals?

Answer 16

Signals which control the feeling of “fullness”, i.e how much of a meal it feels right to eat

Question 17

See binder for details on satiation signals.

Question 18

Name a signal molecule which is released in response to fasting and hypoglycaemia?

Answer 18

Ghrelin

Question 19

What is ghrelin?

What conditions is it released in response to?

Answer 19

Hunger signal

Released in response to fasting and hypoglycaemia

Question 20

Ghrelin increases the magnitude of fat ___.

Answer 20

storage

Question 21

Which type of feedback mechanism controls body weight and energy stores?

Answer 21

Negative feedback

Question 22

Where is information re: body weight and energy storage integrated?

Answer 22

Hypothalamus

Question 23

What are adiposity signals?

Answer 23

Hormones which report the fat status of the body to the hypothalamus

Question 24

The levels of which two hormones increase as more fat is stored?

Answer 24

Leptin

Insulin

Question 25

What do **leptin** and **insulin** instruct the brain to do?

Answer 25

**Eat less** **Increase energy expenditure**

Question 26

Patients with low **leptin** levels will have ___ appetites. Why?

Answer 26

**unrestrained** - insatiable Body thinks it is going through **starvation** as leptin reports level of energy storage

Question 27

What hormone, other than leptin, acts as an adiposity signal?

Answer 27

**Insulin**

Question 28

Which hormone is linked to **food reward** - the pleasure derived from eating?

Answer 28

**Dopamine**

Question 29

People with high fat content will have high levels of circulating \_\_\_.

Answer 29

**leptin**

Question 30

High circulating leptin levels associated with obesity cause receptors to become ___ to it.

Answer 30

**insensitive**

Question 31

What is the only drug currently used in the treatment of obesity?

Answer 31

**Orlistat** (Alli)

Question 32

How does **orlistat** reduce obesity?

Answer 32

**Reduces fat absorption in the small intestine**

Question 33

What are the major side effects of **orlistat** (Alli)?

Answer 33

**Cramps** **Severe diarrhoea** (+/- steatorrhoea)

Question 34

What is **bariatric surgery**?

Answer 34

Surgery which aims to reduce the size of the stomach and therefore combat obesity

Question 35

Name an example of bariatric surgery.

Answer 35

**Gastric band** **Gastric bypass**

Question 36

What effect does **gastric bypass** have on the excretion of satiation signals?

Answer 36

**Reduced secretion of satiation signals** As there's less stomach to do so

Question 37

Which drug uncouples the proton gradient to cause weight loss by overheating?

Answer 37

**2,4-dinitrophenol (DNP)**

Question 38

What is a major side effect of **DNP**?

Answer 38

Death by overheating