Nutrition 2: Obesity and Starvation

Question 1

Regulation of body mass:
What is the first law of thermodynamics?
Energy intake =

Answer 1

energy intake = energy expended + energy stored

Question 2

Define appetite

Define satiety

Answer 2

Appetite = desire to eat food, felt as hunger, that regulates adequate energy intakes to maintain metabolic needs
Satiety = absence of hunger

Question 3

What regulates hunger and satiety?

What 3 factors promote satiety?

Answer 3

NOT GIT!
Regulated by hypothalamus
- hunger centre
- satiety centre

High glucose, high stored fat, presence of macronutrients in GIT

Question 4

1. Which is the main hormone that stimulates hunger?
2. When is it released?
3. When is ghrelin release inhibited?
4. What else can inhibit appetite?
5. What are the 2 main neurotransmitters involved?

Answer 4

1. ghrelin
2. when the stomach is empty
3. when the stomach is full
4. • CCK, PYY, GLP-1 from SI
     - insulin release
     - leptin release
5. serotonine and dopamine

Question 5

What are some physiological and psychological factors can lead to loss of appetite (anorexia)?

Answer 5

Physiological
- anaemia, cancer, liver disorders, mouth disorders, malabsorption syndrome, depression, intestinal disorders, intestinal parasites
Pschological
- stress, anxiety, sadness, wedding, falling in love

Question 6

Most acute diseases/injuties are characterised by a ……………………… state.
Most apparent sign is an abnormally high ………. ………. followed by continuous ………. ……….
Symptoms will usually subside once the underlying illness of injury is treated
Most common causes are:

Answer 6

hypermetabolic
calorie intake, weight loss
infections, sepsis, burns, trauma, fever, surgery, brain injury, long bone fractures, hyperthyroidsim, steroid therapy, bone marrow transplants

Question 7

Why does ageing present particular problems when it comes to illness and appetite? x4

Answer 7

• appetite decreased
• perception of taste is altered
• capacity to eat is decreased
• maintaining positive nitrogen balance is challenging

Question 8

What are some examples of nutritional support in illness/

Answer 8

oral supplements

enteral/parental nutrition

Question 9

What is rickets a deficiency of?

What does it lead to?

Answer 9

Vitamin D

Poor mineralisation of bone, deformation of load bearing bones

Question 10

What is scurvy a deficiency of?

What does it lead to?

Answer 10

Vitamin C

Destruction of collagen, damage to myelin, loss/bleeding tooth sockets, sunken eye sockets, paralysis/death

Question 11

What are the 2 forms of anaemia linked to nutrition?

Answer 11

megaloblastic/pernicious anaemia - lack of vitamin B12 absorption
iron deficiency anaemia

Question 12

What are the 2 forms of inherited obesity?

Answer 12

monogenic mutation - leptin

polygenic - Prader-Willi syndrome

Question 13

What four hormones regulate fat metabolism and how?

Answer 13

insulin - lipogenesis

glucagon, adrenaline, glucocorticoids - lipolysis

Question 14

What is the problem with fructose vs glucose/

Answer 14

fructose is sweeter than glucose
fructose absorbed differently to glucose
fructose does not stimulate insulin secretion –> increase food intake
More conversion into TG’s compared to glucose

Question 15

What BMI defines normal weight, overweight and obese?

Answer 15

BMI 18.5-25 normal weight
BMI 25-30 overweight
BMI >30 obese

Question 16

In ways can body fat be estimated/

Answer 16

BMI comparison with populations of same ethnic origin
Bioelectric impedence
DEXA scans (Xray!)
MRI/CT
waist circumference
waist-hip ratio/skin fold thickness

Question 17

What is meant by apple and pear shapes and who is most at risk of Type 2 diabetes, hyperlipidemia, hypertension, CVD

Answer 17

apple = visceral adiposity
pear = subcutaneous adiposity
apple is more at risk

Question 18

What are the 4 treatments for obesity?

Answer 18

drugs to alter appetite - sibutramine
drugs to alter absorption - orlistat
restrict food intake
exercise 
surgery

Question 19

Starvation

1. Characterised by mechanism to preserve ………… ……….. to maintain ……… and ……….. ……….
2. Results in the consumptoion of ……….. to preserve …………. ……….
3. Marked by increased liver synthesis of ………. and ………… ………… . Also known and …………………… and ………………….

Answer 19

1. plasma glucose, brain, spinal cord
2. tissues, energy production
3. glucose, ketones, gluconeogenesis, ketogenesis

Question 20

Glucose in starvation:

• post prandial: blood glucose and stored glycogen exhausted with …….hrs
• rely on synthesis from endogenous sources beyond this e.g. ……….. and ………

Answer 20

24
amino acids
fats (glycerol)

Question 21

What is doen to maintain glucose supply to the brain?
Breakdown of muscle releases ………. ………. to bolster blood glucose
Breakdown of fat releases ……..
DISADVANTAGEs:
- muscle performance ………
- this is a ……….. resource

Answer 21

amino acids
glycerol
declines
finite

Question 22

Ketone Bodies Production

• Produced from breakdown of ……. …… in the ……..
• B oxidation produces ………-……. which can go into Krebs
• Ketone bodies are ……… soluble
• Can cross the ……… and be used as a source of energy by ………. in ……… as well as in ……… …. …………

Answer 22

fatty acids, liver
acetyl-coa
water
BB
brain
starvation
Type 1 diabetes

Question 23

Why is villous atrophy a consequence of decreasing calorie intake?
What is the impact of this?

Answer 23

decreased rate of cell grwoth, structures like villi are rebuilt less quickly

• decreased SA for absorption
• decreased absorption of nutrients
• diarrohoea –> deficiencies and malnourishment

Question 24

What is leptin?
Where is it produced?
What does it do?

Answer 24

hormone
released from adipocytes
promotes feeling of satiety