Hunger, eating and health

Question 1

digestion is how we convert food into

Answer 1

energy

Question 2

energy supplied to the body in the form of

Answer 2

lipids, amino acids and glucose

Question 3

energy use constant but

Answer 3

intake relatively infrequent

Question 4

energy is stored as

Answer 4

• fat (adipose tissue - 85%)
• protein (muscles - 14.5%)
• glycogen (liver - 0.5%)

Question 5

Glucose is

Answer 5

the brains energy sourcem needs to be readily available
-> stored as glycogen (in the liver) - easily converted back to glucose and released into circulation

Question 6

pancreatic hormones

Answer 6

regulate the conversion process

Question 7

glucagon

Answer 7

stimulates conersion from lycogen to glucose (ready energy)

Question 8

insulin

Answer 8

stimulates conversion from glucose to glycogen (stored energy)
brain - does not need insulin, rest of the body does

Question 9

fat is

Answer 9

preferred enrgy store
- provides 2x as much as energy as glycogen
- glycogen attracts water (heavy)
- fat either comes directly from food or is produced by the body from either glucose and other nutrients

Question 10

3 phases of metabolism

Answer 10

1:cephalic
2: absoptive
3: fasting

Question 11

Cephalic phase

Answer 11

preperatory phase, which is intiated by the sight, smell or expectation of food, ends with absorption into bloodstream

conditioned high release of insulin from pancreas (comparitvely little release of glucogen) in anticipation of glucose increase in the blood stream

insulin lowers level of bloodborne fuels by promoting:
1: use of glucose as primary energy sourse
2: conversion of bloodborn energy sources to storage of fuel
3: storage of glycogen in liver, muscle and fat

Question 12

absorptive phase

Answer 12

nutrients from meal meeting the bodys immediate energy requirments, with the excess being stored

digestion promots release of gut hormone. some of these stimulate insulin release

more insulin is released by the pancreases

Question 13

fasting phase

Answer 13

energy being withdrawn from stores to meet the bodys immediate needs (period between meals)

low level of insulin but high level of glucagon in the blood

because there are low insulin levels
1: glucose no longer main energy source (reserved for brain)
2: conversion of glycogen and protein to glucose promoted
pancreas starts secreting glucagon: high level of glucagon result in
1: release of free fatting acids from aipose tissue (converted to ketons - used by muscles during fasting phase)
2: conversion of glycogon back to glucose

Question 14

theories of eating:
set point assumption (no longer seen as valid models)

Answer 14

• energy set point : based on homeostatic, negative feedback system
• homeostasis
  hunger is driven by the need to have certain
• glucostatic set point
• lipostatic set point

Question 15

glucostaic and lipostatic set point theories

Answer 15

1: glucostatic theory:
- blood glucose (short term regulation)
responsible for intiating and terminating meals (diabieties disputes this theory)

2: lipostatic theory:
body fat (long term regulation)

While the glucostatic theory holds that hunger and satiety are due primarily to short-term shifts in blood glucose levels (or utilization rates), the lipostatic hypothesis states that the humoral signal which influences central structures must be related to long-term changes in the adipose tissue stores.

Question 16

weaknesses of set point theories

Answer 16

• eating disorder, obseity epidemic..
• inconsistence with evolutionary pressures (banking food when available)
• major predictions of theories not conf
  
  • chagnes in glucose needed to increase eating, not natural
  • people with excess fat dont adjust meal size
• fail to recognise the pressures of taste, learning, social influences

Question 17

positive incentive perspective

Answer 17

• developed to overcome shortcomings of set point
• about that inciticpated pleasure of eating and craving
  animals eat in repsonse to:
• preferred falvours
• past expereinces
• time since last meal
• others eating

Question 18

factors that infleunce what we eat

Answer 18

• prfer sweet and salty
• aversion to bitter
• conditioned taste aversion and preferences
• craving for deficiencies :
  
  • sodium, other vitamins
  • dietry deficiencies?
    : manufactoring of food to maximise profits - they maximise taste, and can just have poor nutritional value

Question 19

factors that infleunce when we eat

Answer 19

when food is readily available:
- animals eat many small meals throughout the day, humans tend to focus on a few large meals per day

eating as a stresor:
- eating stresses the body because of the release of insulin
- malaise/ unpleasent feelings -> effects of the cephalic stage

Question 20

Weingarten research

Answer 20

rat experiement (Ate each time conditioned stimulus was presented)
- hunger caused by expectations not energy deficiet
- we eat when we are used to eating

despite fact they had 6 meals aa day they still ate when stimulus came - they were conditioned to eat on the que

Question 21

Satiety is

Answer 21

motivational state that causes us to stop eatin when there is food remaining)

Question 22

Shame models

Answer 22

eat how much they are used to eating

Question 23

appetizer effect

Answer 23

eating a small amount before meal increaes size of meal

Question 24

the mroe variety of food

Answer 24

the more we eat today. problem in today soecity with abundance of food

Question 25

sensory specific satiety

Answer 25

why we often missunderstand that full feeling.

when you feel full not neccsairly means you’r full but how interested you are in contuning to eat that food

@ive just had enough of that food, i want something else@

thats why we can eat desert after meal
when we have a lot of variety more likely to continue eating

Question 26

Structures that play a role in satiety

Answer 26

early work the ventromedial hypothalamus was known as a satiety centre (increased eating)
The lateral hypothalamus was known as the hunfer centre (animals stopped eating and drinking when lesion here)

Hypothalamic nuclei now focus for research

Question 27

problem with VMH as satiety centre

Answer 27

new reserch suggests they overeat becuase they become obese
many effects of VHM lesions are not attributed to VHM damage

Question 28

humans expend most of their energy on

Answer 28

maintaining basal metabolis

Question 29

which area of the hypothalamus seesm to be crtical for the ending of meals?

Answer 29

paraventicular nucleus

• the hypothalamus is a collction of nuclei. different parts have differnet functions

The PVN is the feeding centre - appreciate satiety peptides

when in fasting stage - leptin released nd send message to brain stopping arculate nucleous from send neuro peptide to PVN.