Chapter 33-Fuel metabolism and Obesity

Question 1

What is defined as obesity?

Answer 1

BMI of 35 or more

Question 2

What are the trends of obesity in the US and worldwide?

Answer 2

US-1/3 adults and 17% of children are obese

worldwide-1.6billion (25%) of the world is overweight

Question 3

What are the health consequences of obesity?

Answer 3

1. skeletal muscle insulin resistance and development of type 2 diabetes
2. Diabetes linked end-stage renal disease
3. cardiovascular disease
4. Neurological and psychological issues such as Alzheimer’s disease
5. pulmonary disease ie sleep apnea
6. Reproductive issue ie infertility and gestational disease
7. GI such as colon cancer and gallstones
8. Increases skin infections
9. Orthopaedics ie osterarthritis

Question 4

What are the treatments for obesity?

Answer 4

Lifestyle with low calorie diet and increased physical activity
Pharmacological options that alter nutrient absorption, increase satiety and appetite suppression
surgical treatments ie restrive gastric band and biliopancreatic diversion/duodenal switch

Question 5

What is energy balance

Answer 5

balance of energy intake and energy expenditure (basic metabolism and physical activity)

Question 6

What happens when the energy intake is equal to expenditure?

Answer 6

weight maintenance

Question 7

What happens when energy intake is greater than expenditure?

Answer 7

weight gain (positive energy balance

Question 8

What happens when energy intake is less than expenditure?

Answer 8

weight loss

Question 9

What happens when there is perturbation of body weight

Answer 9

it is met with physiological response to counter the changes

Question 10

What hormones control long term control of intake

Answer 10

insulin and leptin (adiposity signals)

Question 11

What hormones control short term control of intake

Answer 11

peptide tyrosine tyrosine (PYY) and glucagon-like peptide 1 (GLP-1) induce satiety
Ghrelin induce appetitie

Question 12

What are some contributors of obesity?

Answer 12

genetics
leptin (leptin production is proportional to amount of adipose tissue; deficiency of leptin[ar] causes hunger and severe obesity
diet and physical activity (major contributor)

Question 13

what hormones induce hunger

Answer 13

ghrelin

Question 14

What hormones induce satiety?

Answer 14

peptide tyrosine tyrosine (PYY) and glucagon-like peptide 1 (GLP-1)

Question 15

What is the substrate oxidation and fuel preference in fed and fasted state?

Answer 15

skeletal muscles primarily oxidize fatty acids in the fasted state and switch to carbs in the fed state

Question 16

How is substrate oxidation assessed?

Answer 16

indirect calorimety

Question 17

What type of substrate metabolism issues have been observed in obese individuals?

Answer 17

low oxidation metabolism and defects in switching to carbohydrate oxidation (hyperglycemia) in response to insulin

Question 18

low fat oxidation and excess FFAs signifies what? and what does it indicate?

Answer 18

low insulin sensitivity which is indicative of type 2 diabetes

Question 19

what happens to skeletal muscles in response to insulin sensitivity?

Answer 19

increased neutral lipid content
decreased glycolytic activity
decreased glut 4 translocation
decreased capillary density
less mitochondrial content concomitant, lower function and impaired oxidative enzyme activity

Question 20

What does exercise help with?

Answer 20

improving mitochondrial content, substrate oxidation, and insulin sensitivity.

Question 21

What factors contribute to maintaining energy homeostasis?

Answer 21

extrinsic (environmental) and intrinsic (physiological, genetic) changes occur to maintain energy homeostasis