Obesity

Question 1

What is the definition of obesity?

Answer 1

Excessively high accumulation of body fat or adipose tissue in relation to lean body mass; amount of body fat includes concern for both the distribution of fat throughout the body and the size of the adipose tissue deposits; individuals usually at high clinical risk because of excess amount of body fat- BMI over 30

Question 2

What are the parameters for BMI?

Answer 2

18.5 underweight
18.5-24.9 Healthy
25-29.9 Overwieght
30-34.9 Obese
35-39.9 Severe obesity
40-50 Morbid obesity

Question 3

Which ethnic background have high BMI?

Answer 3

Asian

Question 4

How does BMI relate to heart failure?

Answer 4

For every 1 increase in BMI, risk of heart failure goes up by 5% for men and 7% for women

Question 5

What is causing obesity to increase?

Answer 5

Environmental not genetic changes- important because of complications e.g. diabetes

Question 6

In what age group is BMI highest?

Answer 6

55-64

Question 7

Which ethnic groups is BMI highest in?

Answer 7

Caucasian and Bangladeshi

Question 8

In England, which part of the country has highest BMI?

Answer 8

Scotland and North England

Question 9

What else affects BMI?

Answer 9

Smokers have lower BMI but greater central obesity
Higher in social class 5

Question 10

Why is being obese and overweight so common?

Answer 10

Food is cheap
Genetics turned on to eat to protect
Very few systems say stop

Question 11

What are the costs of treating obesity?

Answer 11

49m
Other direct costs of upto 1.2bn
Other indirect costs of upto 1.07bn
Total cost= 3.7bn

Question 12

What are the effects of obesity?

Answer 12

Known to lead to both chronic and severe medical problems
Biggest killer- coronary heart disease
Biggest impact on morbidity and quality of life- diabetes
Osteoarthritis- weight bearing joints
Infertility: in women as PCOS and men are most likely to be impotent
Cancers: breast, endometrial
Depression
Stroke
Sleep apnoea
Gallstones
Hypertension
Gout

Question 13

What are the two different types of obesity in terms of waist circumference?

Answer 13

Android (apple) vs gynoid (pear)
Android is centripetal obesity
Gynoid is where fat is deposited in bottom and legs

Question 14

How is waist circumference measured?

Answer 14

Midpoint between lowest rib and iliac crest; ~1cm above navel and accuracy is difficult if BMI>35

Question 15

What is higher levels of visceral adipose tissue associated with and how?

Answer 15

Increased insulin resistance
There is an impact on liver/glucose metabolism- lipid and insulin homeostasis is impacted. High excess visceral fat results in highest post-prandial insulin release as well as the highest 2 hour blood glucose reading

Question 16

What is abdominal obesity associated with?

Answer 16

Increase in:
insulin insensitivity
Abnormal lipid profile
Susceptibility to thrombosis
Inflammation markers
Endothelial function

Greater risk of CHD

Question 17

What is the normal relationship between energy in, out and stored?

Answer 17

When weight stable, energy in= energy out + energy stored

Question 18

When does weight gain occur?

Answer 18

Energy in exceeds energy out due to increased intake or decreased expenditure

Question 19

What is adaptive thermogenesis?

Answer 19

Amount expended by digesting food.

Question 20

What are the three components of daily EE?

Answer 20

Resting metabolic rate (RMR)- 50-70%
Thermic effect of food 5-15%
Energy cost of physical activity- 20-40%

Question 21

What orexigenic/anabolic molecules are there?

Answer 21

Neuropeptide Y (NPY)
Agouti gene related peptide (Agrp)
Agouti-related transport (ART)
Melanin-concentrating hormone (MCH)
Dopamine

Question 22

What anoretic/catabolic molecules are there?

Answer 22

Leptin receptor (LEPR)
Pro-opiomelanocortin (POMC)
Melanocortin receptor 4 (MCR4)
Corticotrophin release hormone (CRH)
Serotonin receptor subtype 2C (5-HT2C)
Glucagon-like peptide 1 receptor (GLP-1R)

Question 23

What genes are expressed in skeletal muscle regarding body weight?

Answer 23

Myostatin
Myogenin
Myogenic factors 4 and 5

Question 24

What genes are expressed in brown adipose tissues regarding body weight?

Answer 24

Uncoupling protein 1 (UCP1)

Question 25

What genes are expressed in white adipose tissue regarding body weight?

Answer 25

Leptin
Lipoprotein lipase
Fatty acid binding protein 4
Peroxisome proliferator-activated receptor gamma

Question 26

What genes are expressed in gut regarding body weight?

Answer 26

Cholecystokinin receptor A

Glucagon-like peptide 1 (GLP-1)

Question 27

What has been linked to increasing rates of obesity?

Answer 27

Energy intake has remained similar even decreased but there is increased inactivity (TV viewing and increased number of cars per household
Especially in lower social classes (don’t have higher energy/fat intake)

Question 28

What has changed in diet over last 50 years?

Answer 28

Food is cheap
Energy between meals has increased
Energy density of food increased
Increased processing of food

Question 29

What factors influence obesity risk?

Answer 29

Convincing evidence:
Regular exercise and high dietary fibre decrease risk; sedentary lifestyles and high intake of energy dense foods increase risk
Probable evidence:
Home and school environments supporting healthy food choices and breastfeeding may decrease risk; marketing of fast food and adverse socio-economic situation
Low GI foods decrease risk, protein has no effect

Question 30

What are the effects of 10% weight loss?

Answer 30

Improves all aspects of metabolic syndrome, including:
50% fall in FBS (fasting blood sugar)
10% decrease in total cholesterol
15% reduction in LDL
30% fall in triglycerides
8% rise in HDL
Improvement of BP by 10/20mmHg
20-25% reduction in mortality
30-40% reduction in diabetes related mortality
40-50% reduction in certain cancers