lecture 12 - Weight management obesity

Question 1

What is obesity?

Answer 1

accumulation of excess body fat

Question 2

Why do genetic factors favour food storage?

Answer 2

because we store food for times when we are lean due to evolution when we didn’t always have food available.

Question 3

Obesity … with age

Answer 3

increases

Question 4

obesity is more common in the …. educated and …. societies

Answer 4

less educated and poor societies

Question 5

Three are …. obese than undernourished people

Answer 5

more

Question 6

How to assess obesity?

Answer 6

BMI - weight in KG / M^2

Question 7

BMI ranges?

Answer 7

20-25 - normal
25-30 - overweight
30-40 - obese
40 + - severe obesity

Question 8

What are some anatomical differences in the way we deposit fat?

Answer 8

Android (apple shape) - located in the central abdominal area

Gynoid (pear shape) - located in the lower extremities, waist to hip ratio: men 1.0 and women 0.8 or waist circumference: men over 40 inches and women 35

Question 9

What is android fat deposit associated with?

Answer 9

increased risk of hypertension, insulin resistance, diabetes, dyslipidemia, and CHD

Question 10

How are the different regional fats biochemically different?

Answer 10

abdominal fat cells:

• larger and higher rate of fat turnover than lower body fat.
• Abdominal adipocytes are hormonally more responsive than fat in the legs or butt
• FAs taken up by the liver could lead to insulin resistance and increased synthesis of TAGs which are released as VLDL

gluteal fat:
-FFAs from gluteal fat enter the general circulation and there is no preferential action on hepatic metabolism

Question 11

difference between subcutaneous fat and visceral fat?

Answer 11

sub - generally harmless
visceral - in abdomen including around the liver, stomach and intestines promotes inflammation and metabolic disturbances and it is associated with health complications like type 2 diabetes and heart disease.

Question 12

What are the changes that occur in the accumulation of fat?

Answer 12

• increase in the number of cells
• increase in the size of the cells

it is easier to reduce the size fo the cells

Question 13

Hypertrophic vs hyperplastic fat cells?

Answer 13

trophic - size

plastic - number of cells

Question 14

Weight …… following episodes of overfeeding or underfeeding but …… to the set point

Answer 14

changes

but geos back to the

Question 15

Main cause in the rise of obesity ?

Answer 15

cant be genetic factors and chemical or hormonal factors because they are the same.

• main cause is the food industry in which a lot of our food now has additives and perservatives and we like to enjoy food. We use food as a dopamine hit

Question 16

obesity behaves as a …. ….. …. with multiple ….. involved

Answer 16

complex polygenic disease with multiple genes involved

Question 17

mutation of what genee can cause obesity?

Answer 17

The gene that contorls leptin, if there is leptin deficiency you can become obese

Question 18

What is leptin?

Answer 18

An adipocyte peptide hormone that is made and secreted in proportion to the size of fat stores. More fat means more leptin.

Question 19

What genes are associated with obesity?

Answer 19

Ob gene

Question 20

Why is the Ob gene so important in obesity?

Answer 20

-because it produces leptin which acts on the satiety centre (hypothalamus)

Question 21

what is so important about the db gene ?

Answer 21

• mutation in the db gene will cause leptin resitance in which many obese people have leptin resitance
• leptin decreases appetite
• insulin also decreases appetite

Question 22

signals that are sent by the hypotahlamus when underenourished

Answer 22

if no leptin, this is not controlled

Question 23

signals sent by hypothalamus when overnourished ?

Answer 23

if no leptin then it is not controlled

Question 24

Hormones that impact obesity?

Answer 24

ghrelin - appetite stimulating

cholecystokinin (CCK) - saiety signal

insulin - increases metabolism and decreases energy intake

Question 25

Answer 25

Question 26

What are the primary metabolic effects of obesity?

Answer 26

- dyslipidemias - glucose intolerance - insulin resistance expressed primarily in the liver, skeletal muscle, and adipose tissue - meetabolic syndrome - non alcoholic liver disease

Question 27

What is the metabolic syndrome and what is it associated with?

Answer 27

charecterised by obesity, especially abdominal obesity associated with: - hypertension - insulin resitance - hyperglycaemia and high levels of insulin - low levels of HDL but high levels of TAG and high levels of small, dense and atherogenic LDL - elevated plasma concentration of non esterfieed FAs - low grade systemic inflammation with high levels of circulating inflammatory cytokines - increased oxiditave stress - decreased fibrinolysis of blood clots

Question 28

Visceral adipose tissue has ..... lipolytic activity and so it releases ...... which inhibit ........ and .......

Answer 28

- high - glucose metabolism - insulin receptor signalling pathway

Question 29

What does leptin antagonise?

Answer 29

actions of insulin

Question 30

Whaat cytokines secreted by adipose tissue cause insulin resistance?

Answer 30

- TNF-alpha - interleukins IL-1 and IL-6 - monocyte chemotactic protein and resistin

Question 31

cortisol is secreted by ..... in an ..... manner

Answer 31

- adipose tissue - unregulated

Question 32

What does cortisol increase?

Answer 32

- hepatic gluconeogenesis and glucose release - lipolysis and relase of non esterfied FAs in adipose tissue

Question 33

What is dyslipidemia?

Answer 33

- insulin resitance in adipose tissue causes increased activity of hormone sensitive lipase whic leads to an incerase in circualting FAs - FAs are carried to the liver where it is converted to TAGs and cholestrol - These are released as VLDL and results in increase in serum TAGs - HDLs are decresased

Question 34

What is non alcoholic liver disease?

Answer 34

- it is when obesity is associated iwth ectopic deposition of TAG in the liver and this leads to hepatic steatosis - results in increased risk of non alcoholic fatty liver disease (NAFLD)

Question 35

What are some health risks of obesity?

Answer 35

1. ) cancer - breast, prostate and colorectal 2. ) atherosclerosis - CHD, high blood pressure, and stroke 3. ) complciations of T11 DM 4. ) respiratory disease

Question 36

As more food is eaten what increases ?

Answer 36

- increased cost of digestion - increased cost of absorption - increased cost of synthesis of TAG and glycogen reserves - increased protein turnover

Question 37

as body weight increases what else increases?

Answer 37

- increased BMR - increased cosst of physical activity

Question 38

What is the initial rapid weight loss associated with?

Answer 38

- loss of water associated with glycogen