Wk 3 - Nutrition: Appetite

Question 1

Define appetite.

Answer 1

Appetite is the desire or inclination for food - a process that directs eating, determining which food are chosen, the rate they are ingested and the amount that is consumed

Question 2

What is appetite influenced by?

Answer 2

• Hunger
• Sensory cues (taste, smell, texture)
• Time of day
• Social situation

Question 3

Define satiation.

Answer 3

The process leading to the termination of an episode of eating - determines meal size.

Satiation can be overridden e.g. eating dessert – because foods with specific characteristics have different stimulatory powers.

Question 4

Define satiety.

Answer 4

• The process that maintains the post-meal inhibition of eating (even if food is available all the time, human don’t eat continuously).
• Prevents return of hunger for a variable period of time – allowing the matching of intake to energy needs.

Question 5

What is the cephalic phase?

Answer 5

Pre-eating phase

Question 6

How is the cephalic phase initiated?

Answer 6

Cephalic phase response initiated by the sight, smell, sound, thought and taste of food

Question 7

How is the cephalic phase involved in appetite control?

Answer 7

• GI secretions (saliva, gastric acid, pancreatic juice)
• Hormone (insulin, glucagon, cholecystokinin) and metabolite concentrations (glucose) change
• Respiratory quotient and energy expenditure change
• Changes in hunger
• Drop in gastric ghrelin

Question 8

What is the rate-limiting aspect of ingestion?

Answer 8

The stomach:

• Stomach places a physical constraint on the amount actually ingested
• Rate of food ingestion is partially limited by the rate of digestion by the stomach, which regulates the rate nutrients are delivered to the small intestine (nutrients are delivered to the small intestine in proportion to their energy content)

Question 9

List the hormones that induce satiety (anorexigenic).

Answer 9

• Leptin
• Glucagon-like peptide-1 (GLP-1)
• Cholecystokinin (CCK)(suppress)
• Peptide YY (PYY)

Question 10

What hormone stimulates appetite ie is orexigenic?

Answer 10

Ghrelin

Question 11

List the factors that affect appetite?

Answer 11

• Age
• Food composition (macronutrients)
• Food consistency (liquids, solids)
• Exercise
• Pregnancy and lactation
• Growth
• Starvation
• Disease/illness and associated medications
• Psychological factors
• Stress
• Others?