Lecture 3

Question 1

What factors influence meal size and meal duration?

Answer 1

[A] The development of inhibitory influences on eating behaviour

[B] The role of positive feedback in maintaining feeding behaviour

Question 2

Stomach distension (Enlargement) is relatively unimportant

How much water does it take to reduce food intake?

Answer 2

Inflated balloon show that > 400 ml is required to reduce food intake.

Question 3

Study looking at short term influences on eating (Camps et al., 2016):
MILKSHAKES

Answer 3

Stomach emptying is governed by calories

Fullness is governed by Viscosity

There is a mis-match between what the pps are reporting and what is in their stomachs

Question 4

What is phantom fullness?

Answer 4

Gastric emptying rate varies
But when you look at gastric volume; stomach emptying is governed by the number of calories consumed
Over this same period, the fullness of pps was governed by viscosity;

Question 5

Effects of viscosity and eating rate

Answer 5

More food consumed in liquid form than semi-liquid

Food form can influence food intake/satiation

Question 6

Meal size is also under hormonal control

CCK- a satiety hormone

Answer 6

Its release is stimulated by the presence of fat, peptides, and amino acids.

CCK has multiple effects, modulation of stomach emptying and emptying of the gall bladder

Question 7

Brain areas showing Enhanced activation to food stimuli when satiated

Answer 7

Left side
DLPFC (areas associated the evaluation of foods)
Right side
INSULA

Question 8

The satiety hierarchy

Answer 8

Protein (most satiating)
Carbs
Fat
Alcohol

Question 9

Energy compensation in children (Lipps birch & Mary Deysher)

Used pre-load paradigm

Answer 9

Children:
Eat the same amount in both conditions (“Good compensation”)
Compensate for the calories in the pre-load

Adults:
Do not compensate for higher calories pre-load and eat more

Question 10

What is the role of positive feedback in maintaining eating behaviour?

Answer 10

Subjective experience tells us that eating behaviour is influence by positive feedback

• We all like to eat

Question 11

What influences meal termination?

Answer 11

Negative feedback arguably leads to meal termination

Question 12

The ‘appetizer effect’

Answer 12

Palatability can actually increase hunger during a meal

Question 13

Appetition

Answer 13

Appetition signals act within a meal to promote continued intake in immediate response to gut feedback

Detection of nutrients directly in the stomach that promotes and increases food intake

Form of positive feedback

Question 14

Alliesthesia

Answer 14

Describes the dependence of the perception of pleasure or disgust perceived when consuming a stimulus on the “milieu intérieur” of the organism.

Question 15

Cabanac (1971)

Answer 15

Pleasure serves the role of orientating an individual around stimuli that serve to correct any perturbation in internal state

A homeostatic account of pleasure

Question 16

Is pleasure fixed?

Answer 16

If you give someone a glucose load
It will decrease pleasantness of sucrose (sweet tasting substance) but not salt
Eating decreases pleasantness of food-odours but not non-food odours

Pleasure is not fixed; it serves a functional role; not property of stimulus
Instead, it depends on signals relating to internal state.

Pleasure serves the role of orientating an individual around stimuli that serve to affect the perturbation of food

Question 17

Sensory-specific satiety:

Answer 17

SSS is specific to the particular food that you have just consumed

Question 18

Sausage study- EARLIEST SSS STUDY: Rolls, Rolls, Rowe & Sweeney, 1981

Answer 18

Amount consumed in second course:

Same food:
Reduction in amount eaten

Different food:
Considerably large amount consumed during the second course

Suggested that satiation is specific to the food that you have just consumed; NOT GENERAL!

Question 19

What is key about SSS?

Answer 19

SSS is NOT mediated by low level sensory habituation process

Not the case that it is changed by the taste property of food
Ie. The dated idea that after eating a food the taste characteristics becomes less intense
Leading you to be drawn to foods with different sensory characteristics

Question 20

Berridge (1996)

Looked at wanting and liking

Answer 20

Liking = reflects affective processes of palatability/pleasure/displeasure. 
Wanting = a disposition to eat (incentive salience) 

Looks at how hard are humans/ animals prepared to work for food

Question 21

What does positive and negative feedback do?

Answer 21

It appears that positive feedback (hedonics) and negative feedback (satiation signals) may be separate processes in mediating meal size in humans