Obesity

Question 1

Prevalence of obesity in Canada?

Answer 1

23%

Question 2

What percentage of Americans are overweight or obese?

Answer 2

70%

Question 3

What is the MOA behind obesity increasing cancer risk?

Answer 3

increased insulin resistance means more insulin in the blood as well as increased IGF1; their receptors are stimulated on target cells, increasing cell proliferation and decreasing apoptosis –> tumour development

Question 4

biochemical factors that inhibit appetite?

Answer 4

serotonin
dopamine
cholecystokinin
corticotropin releasing factor
neurotensin
bombesin
calcitonin gene related peptide
amylin
adrenomedullin
glucagon
glucagon-like peptide 1

Question 5

biochemical factors that increase appetite?

Answer 5

noradrenaline
opioids
GHRH
galanin
melanin-concentrating hormone
neuropeptide Y

Question 6

cortisol decreases _________ sensitivity by receptor cells

Answer 6

insulin

and therefore glucose uptake

Question 7

cortisol increases urinary excretion of _________

Answer 7

magnesium

important in synthesis of healthy PGs

Question 8

cortisol competes with thyroid hormone for the amino acid __________, which is involved in thyroid hormone formation.

Answer 8

tyrosine

therefore limits amount of thyroid hormone –> decreased energy and increased body fat

Question 9

T or F: insulin crosses the BBB

Answer 9

true

binds to receptors in hypothalamus - activates appetite centre within brain

Question 10

Leptin acts in hypothalamus to…?

Answer 10

suppress food intake and increase energy expenditure
sends satiety signals to the brain

levels high in nearly all obese people

Question 11

what is the action of ghrelin?

Answer 11

appetite stimulant

secreted by stomach and duodenum
levels rise before meals
suppressed after eating

Question 12

dopamine plays an important role in which physiological functions

Answer 12

motor control
motivation
arousal
cognition
reward
lactation
sexual gratification
nausea

does not cross BBB

Question 13

PET scans of obese individuals demonstrate a difference in dopamine receptors in obese and lean people. What is the difference?

Answer 13

less dopamine receptors found in obese people as compared to lean

obese individuals need to eat more to derive pleasure and reward from food

Question 14

MOA of obesogens?

Answer 14

• alter action of metabolic sensors
• disregulate sex steroid synthesis
• inappropriate modulation of nuclear receptor function (mimic hormones in the body, alter normal homeostasis)

Question 15

Overweight BMI?

Answer 15

25-29.9

Question 16

Morbidly obese BMI?

Answer 16

higher than 46-47

Question 17

Obese BMI?

Answer 17

30 or more

Question 18

how many calories per day must be cut in order to lose 1-2 lbs per week?

Answer 18

500 cals

Question 19

for adults, success in weight loss is defined as?

Answer 19

losing at least 10 percent of initial weight without regaining more than 6 or 7 lbs. in 2 yrs.

Maintenance of a lower waist circumference (at least 2 inches lower than before weight loss)

Question 20

natural supplements to increase satiety?

Answer 20

guar gum
glucomannan
psyllium
garcinia cambogia

Theory:
Soluble fiber can absorb water within the gut

Causing increased satiety and lower caloric intake

Fiber also may improve control of diabetes and hyperlipidemia
Findings:
Guar gum versus placebo for weight loss showed no benefit.

Glucomannan in dosages of 3 to 4 g per day may be well tolerated and yield modest weight loss

Psyllium improved glucose and lipid parameters significantly more than placebo in 125 overweight patients with type 2 diabetes, but there were no differences in weight loss

Question 21

describe leptin

Answer 21

the “satiety hormone”

made by adipose cells that helps to regulate energy balance by inhibiting hunger. Leptin is opposed by the actions of the hormone ghrelin, the “hunger hormone”. Both hormones act on receptors in the arcuate nucleus of the hypothalamus to regulate appetite to achieve energy homeostasis. In obesity, a decreased sensitivity to leptin occurs, resulting in an inability to detect satiety despite high energy stores.