2.11 - Obesity, Weight Loss and Bariatrics

Question 1

What are the components of a balanced diet?

Answer 1

• Fruits/Vegetables
• Carbohydrates
• Proteins
• Dairy
• Fats

Question 2

How are carbohydrates digested?

Answer 2

• Started by salivary amylase
• Majority of digestion occurs in small intestine
• Main enzyme is pancreatic amylase
• Hydrolysed into glucose, galactose and fructose

Question 3

How are digested carbohydrates absorbed?

Answer 3

• Glucose/Galactose enter via SGLT-2 co-transporter. Exit via GLUT2
• Fructose moves via GLUT5

Question 4

How are proteins digested?

Answer 4

• Begins in stomach with pepsin which makes amino acids and oligopeptides
• Completed in small intestine where di/tripeptides are formed

Question 5

How are proteins absorbed?

Answer 5

• Amino acids via a sodium co-transporter then across basolateral membrane via facilitated diffusion
• Di/tripeptides via seperate H+ dependant co-transporters and are then hydrolysed

Question 6

How are lipids digested?

Answer 6

• Are hydrophobic and are poorly absorbed
• Started by lingual/gastric lipases
• Remainder in SI by bile via emulsification into micelles
• Micells into fatty acids

Question 7

How are lipids absorbed?

Answer 7

• Released at apical membrane and diffuse into enterocyte
• Inside the cell the reform original molecules and form a chylomicron
• Enter lymphatic system

Question 8

How is water absorbed?

Answer 8

• Most absorption of water and electrolytes occurs in the small intestine
• Some absorbed in the colon as well
• Dependant of absorption of Na+ and Cl-
• Moves via osmosis

Question 9

How is BMI calculated?

Answer 9

Weight (kg) / Height (m) x Height (m)

Question 10

What does a BMI below 18.5 indicate?

Answer 10

• Underweight

Question 11

What does a BMI between 18.5 - 24.9 indicate?

Answer 11

• Healthy weight

Question 12

What does a BMI between 25.0 - 29.9 indicate?

Answer 12

• Overweight

Question 13

What does a BMI above 30 indicate?

Answer 13

• Obesity

Question 14

What is malnutrition?

Answer 14

• Chronic undernutrition which can lead to significant deficiencies in essential nutrients
• Impairs physiological functions

Question 15

What are some complications associated with being underweight?

Answer 15

• Osteoporosis
• Muscle wasting
• Hormonal imbalance
• Malabsorption
• Immune dysfuction
• CVS complications

Question 16

What are some complications associated with being overweight?

Answer 16

• T2DM
• Dyslipidaemia
• HTN
• NAFLD
• Psychosocial effects
• Joint diseases
• Obstructive sleep apnoea

Question 17

What are the features of abdominal obesity?

Answer 17

• Apple-like appearance
• Subcutaneous
• Intra-abdominal fat/visceral
• Accounts for most of mortality and morbidity

Question 18

What are the features of gynaecoid obesity?

Answer 18

• Pear-like appearance
• Not associated with adverse metabolic events
• Fat in lower portion of body

Question 19

What is basal metabolic rate?

Answer 19

• Minimum energy needed for essentail activity at rest

Question 20

What controls appetite in the brain?

Answer 20

• Hypothalamus

Question 21

Which area of the hypothalamus controls satiety?

Answer 21

• Ventral posteromedial nucleus

Question 22

Which area of the hypothalamus controls hunger?

Answer 22

• Lateral hypothalamic area

Question 23

Which hormones are responsible for appetite stimulation?

Answer 23

• Orexigenic hormones

Question 24

Which hormones are responsible for appetite inhibition?

Answer 24

• Anorexigenic hormones

Question 25

What is peripheral satiety and what mechanisms control it?

Answer 25

• Satiety that arises from the gut
  1. Gastric distension
  2. Balance of chemicals
  3. Peptides and hormones