obesity

Question 1

leptin: what is it?

Answer 1

hormone secreted by adipose tissue that tells the body that there is enough energy. higher levels are secreted in pts with high levels of adiposity. This is not the same as a signal to loose weight, which would be a corrective measure. leptin secretion is suppressed by fasting and by cold.

Question 2

leptin resistance

Answer 2

develops in response to chronically elevated leptin levels. obesity will keep re-establishing a set-point. with leptin resistance, the brain perceives energy insufficiency and drives changes to increase adiposity until higher leptin levels signal adequate energy sufficiency again. This leads to slow weight gain over yrs. Periodic fasting may help break leptin resistence

Question 3

adiponectin

Answer 3

product of the adipocyte. lower serum levels at increased fat mass. serum levels raised by weight loss. adiponectin insils INSULIN sensitivity and drives fatty acid oxidation in muscle.

Question 4

ghrelin

Answer 4

from gastric cells, esp. in the fundus. plasma levels peak in fasting and are suppressed by feeding, esp protein. ghrelin levels are lower in obesity and higher in lean ppl. gastric bypass suppresses ghrelin. no clear defect associated with obesity. proorexigenic (pro-appetite)

Question 5

satiety hormones

Answer 5

mostly GLP-1 and peptide YY (PYY). mostly secreted by cells in the ileum and colon. increased levels seen after gastric bypass. no clear defect seen in obesity.

Question 6

incretins

Answer 6

pancreas responds to nutrients faster than can be accounted for by digestion, absorption and circulation, suggesting a link btw the gut and the pancreaus. Also, oral glucose gets a much greater insulin response than IV glucose (why you get so much more hyperglycemic on TPN). Incretin is the term used to denote glucose lowering, insulin stimulating intestinally derived peptides.

Question 7

GIP

Answer 7

first incretin. released from proximal gut (early intestine) K cells. incretin effects are incomplete: also relies on GLP-1. causes incr. insulin secretion and insulin synthesis. Increases B cell prolif and decreases B cell apoptosis. It increases bone formation and increases lipogenesis. bypass out GIP in gastric bypass surgery: osteoporosis is a potential complication.

Question 8

GLP-1

Answer 8

Satiety hormone. From intestinal L cells of ileum and colon. also helps with the incretin effect. blunded in obese: post-prandial hyperglycemia and associated with DM2. deficiency is secondary to leptin resistence.

Question 9

Management for high BMIs

Answer 9

comprehensive lifestyle modification with a goal of reducing body weight by 10%. to maintain weight loss, we must have high levels of physical activity, patient-progessional interactions, pharmacotherapy and lifestyle modification.

Question 10

very low calorie diets

Answer 10

400-800 calories/day with high proteins. lead to rapid weight loss of 15-25%. But, causes more symptomatic gallstones and causes greater weight regain than other options.

Question 11

Why is exercise important for weight loss?

Answer 11

without restriction, it you won’t loose much weight. we think exercise helps spare lean mass, negate occasional indiscretions, and improve mood to combat psychological impediments.

Question 12

Which is better, lifestyle changes or programmed activity?

Answer 12

lifestyle changes better for durability of weight loss: incr. activity w/o concern for duration or intensity. take stairs, park remotely, etc.

Question 13

Locaserin

Answer 13

approved in 2012 after initial rejection. serotonin 2c agonist (which was the basis of fen-phen valve injury).

Question 14

qsymia

Answer 14

approved in 2012 after initial rejection.

causes birth defects, depression, HTN, maybe valve injury. 14% weight loss vs. placebo at 1 yr.

Question 15

Why might drug therapy for obesity be a bad idea?

Answer 15

weight loss reverses after cessation, may have bad side effects, money, and small impact on health.

Question 16

when is weight loss surgery recommended? weight loss outcomes. types of surgeries (general)

Answer 16

BMI over 40. can result in loss of 50-75& of excess body weight. more than 95% of pts with BMI 35-50 get under BMI of 35. However, 10-40% of pts don’t sustain weight loss in the long-term.
surgeries may be restrictive or malabsorptive.

Question 17

other outcomes of weight loss surgery

Answer 17

often see a resolution of diabetes, which often precedes weight loss. also see reduction in CA, CV disease, infections, pulmonary disease

Question 18

complications of weight loss surgery

Answer 18

erosion of restrictive bands, strictures, ulcerations, gallstones, iron deficiency, osteopenia, post-prandial hypoglycemia