L11 - Appetite and weight

Question 1

How to measure obesity?

Answer 1

BMI 
Waist circumference 
skin-fold thickness 
ethnicity specific cut offs
bioelectrical impedance analysis

Question 2

Medical consequences of obesity

Answer 2

metabolic syndrome/T2D
cardiovascular  disease
respiratory disease
liver disease
cancer
reproductive dysfunction 
joint problems 
more likely to have co morbidities

Question 3

metabolic syndrome

Answer 3

visceral obesity - central 
dyslipidemia 
hyperglycemia
hypertension 
Insulin resistance is the underlying patho mechanism
BMI more than 30

Question 4

Patho of metabolic syndrome and insulin resistance

Answer 4

inc free fatty acids 
lipolysis of visceral fat 
gluconeogenesis 
dyslipidemia 
proinflammatory cytokines 
TNFa and IL6 lead to increase insulin resistance
reduced expression of glut4 
reduced tyrosine kinase activity of insulin receptor

Question 5

Respiratory problems

Answer 5

obstructive sleep apnoea
hypoxia
pulmonary hypertension - right heart failure

Question 6

effects on GI / Liver

Answer 6

non-alcoholic fatty liver 
non-alcoholic steatohepatitis 
may progress to cirrhosis, portal hypertension, hepatocellular cancer 
gallstones 
reflux

Question 7

cancer and obesity

Answer 7

breast, endometrial, oesphagus, colon, gall bladder, renal, thyroid
mechanisms include increased insulin, increased oestrogen, increased free IGF1

Question 8

reproductive system and obesity

Answer 8

Polycystic ovarian syndrome
male hypogonadism
adverse pregnancy outcomes

Question 9

Joint problems and obesity

Answer 9

osteoarthiritis

gout

Question 10

Psychological problems and obesity

Answer 10

eating disorders

depression

Question 11

Genetic causes

Answer 11

Rare; prader-willi syndrome
Bardet-Biedl

Common - polgenic
susceptibility genes

other causes: hypothyroidism
cushings syndrome

Question 12

Environmental causes of obesity

Answer 12

diet - high fat/sugar 
socioeconomic factors 
physical activity 
car ownership 
tv viewing

Question 13

Fetal programming and obesity

Answer 13

Programming’: stimuli / insults at critical periods have persistent biological effects
Mechanism: epigenetic modification of gene expression

Question 14

Gut microbiome and obesity

Answer 14

Differences in gut bacteria
Can be induced by diet e.g. high fat diet
Transplantation of faecal material alters insulin sensitivity

Question 15

Regulating appetite and weight

Answer 15

slow acting hormones that regulate body weight are
LEPTIN
INSULIN
signals % body fat to the hypothalamus to reduce food intake or increase energy expenditure
Rapid acting peptides that regulate meal sizes
Ghrelin encourages eating whilst CCK reduces eating
PYY reduces eating
they are released from GI tract
THESE SIGNAL BACK TO HYPOTHALAMUS WHERE THERE ARE ACCELERATOR NEURONS (NPY/AgRP neurons) WHICH STIMULATE EATING
BRAKE NEURONS - POMC NEURONS INHIBIT EATING

Question 16

Treatment

Answer 16

diet 
exercise 
30 mins moderate - high intensity or 60 mins low intensity 
target 10,000 steps a day
increased 500 step increments 
VLCD

orlistat - binds and inhibits lipases in the lumen of the gut
prevents hydrolysis of dietry fat into absorbable free Fatty acids /glycerol

Metformin
best first line for overweight/obese pts with T2D

Question 17

what are the adverse effects of orlistat?

Answer 17

flatulence
oily faecal leakage diarrhoea
reduced absorption fat soluble vitamins
ADEK supplements

Question 18

surgical treatment

Answer 18

laparoscopic adjustable banding

Question 19

Roux-en-Y gastric bypass

Answer 19

alteration in gut hormones and bile acid flow contributes to weight loss
micronutrient deficiencies - supplement with iron, vit D, B12 folate calcium
Dumping syndrome - GI/Vasomotor symptoms