PSY2003 W11 Hunger, Eating and Health (L)

Question 1

What makes up a toxic environment?

Answer 1

Very easy to eat or drink large amounts of high calorie food in modern times.

Kelly Brownell coined this term to describe the way in which human evolution and the environment that we are now in are completely at odds:
-In cultures where food is scarce, obesity is valued as a status symbol.
-In cultures where food is plentiful, obesity is stigmatized as a sign of weakness

Question 1

What is involved in the human digestive system?

Answer 1

Mouth and salivary glands
Oesophagus
Stomach
Liver/gall bladder
Pancreas
Small intestine
Large intestine
Liver and kidneys
Rectum/anus and bladder

Question 2

What does the mouth and salivary glands do?

Answer 2

Mastication and saliva (alkaline)

Question 3

What does the oesophagus do?

Answer 3

Transporting food to stomach
Set up for alkaline conditions, so acid from the stomach can damage it

Question 4

What does the stomach do?

Answer 4

Churning food and breaking it down
Acid digestive enzymes

Question 5

What does the liver/gall baldder do?

Answer 5

additional digestive enzymes added into the small intestine

Question 6

What does the pancreas do?

Answer 6

Produces insulin and glucagon to store and relase energy

Question 7

What does the small intestines do?

Answer 7

Absorbs most nutrients from the food that we eat

Question 8

What do the large intestines do?

Answer 8

Removes water and packs waste

Question 9

What does the liver and kidney do?

Answer 9

Filter out towins for excretion

Question 10

What does the ractum and anus and bladder do?

Answer 10

Store adn expel waste

Question 11

What does insulin do as a key pancreatic hormone in the process?

Answer 11

Shifts carbohydrate from the blood to storage (glycogen, proteins)

Question 12

What does Glucagon do as a key pancreati hormone?

Answer 12

Shifts fuel from storage to where it is needed to fuel the body.
Converts glycogen and proteins to carbohydrate.
Frees fat stores (free fatty acids) to use as fuel when the glucose stores are low

Question 13

WHY DOES OUR INTAKE HAVE TO BE SO COMPLEX?

Answer 13

Because we are omnivorous. Our diet includes a range of key elements: our bodies have evolved to process them. A lot of variation between species e.g., number of stomachs. Some variation within species e.g., dairy tolerance

Question 14

What are the 3 core rpoducts ?

Answer 14

Lipids/Fats
Amino acids
Glucose
(+minurals and vitamines)

Question 15

How are lipids/fats stored?

Answer 15

Fats – largest and most efficient energy store

Question 16

How are amino acids stored?

Answer 16

Proteins – mostly in the form of muscle tissue

Question 17

How is glucose stored?

Answer 17

Glycogen – stored in muscles and liver, fast release

Question 18

How does mineral and vitamines are stored?

Answer 18

Body structure – bones, cell structure ect

Question 19

How do we ensure that those needs are met?

Answer 19

Homeostasis/set point theory
Hunger
Craving

Question 20

And why does it all go wrong sometimes?

Answer 20

Internal factors (e.g., learning, emotions)
Environmental factors (the ‘toxic environment’)

Question 21

What are some mechanism for eating?

Answer 21

Evolutionary terms: body developed the ability to balance our intake and output. Homeostasis kicks in when our body’s set point is violated. going over or below the set point: fat metabolism will change to push it up or down. Body tried to stay in a particular zone.

Question 22

How do we know when we are running low on certain foods?

Answer 22

Detectors in our body tell us when we are running low on nutrients/fuel, and trigger our biology and behaviour

Brain is sensitive to shortage of glucose (hypothalamic regulatory nuclei)
Liver is sensitive to shortages of both glucose and lipids
Stomach sends signals to the brain (release of ghrelin) re need for food if it is unstimulated

Question 23

What is homeostasis and set point thoery?

Answer 23

When we are running low on fuel, we experience:

Hunger (a motivational state)
due to low levels of fatty acids/glucose
craving (a more automatic behavioural state)

The body corrects by:
releasing glucose (see above)
taking in more food

Question 24

Why do we stop eating?

Answer 24

The body generates a range of short-term satiety signals:
Adequate glucose and lipid acid levels: detected in the brain and liver.
Stomach distension
Buccal activity: lots of chewing
High levels of sensory stimulation: big on taste and smell
Appetite suppressant chemicals: e.g., caffeine, amphetamines

Most diet products try to offset the first with the others (with very limited and very temporary success)

Question 25

Is there a centre for satiety?

Answer 25

Previous research/theory suggest that there was a centre in the brain for satiety (hypothalamus), more recent studies suggest no centre. Instead, it looks as if the process is more hormonally controlled: e.g., ghrelin, neuropeptide Y, serotonin. A long-term feedback mechanism to attend to. Fat tissues secrete a hormone – leptin

Question 26

What is leptin’s two affects?

Answer 26

Increases body metabolic rate

Decreases food intake in two ways: desensitizes the brain to hunger signals and inhibits the effect of other hormones that drive eating, particularly Neuropeptide Y

Question 27

What is the satiety cascade?

Answer 27

Food > sensory > cognitive > post-ingestive > post absorptive

Question 28

What is homeostasis?

Answer 28

Homeostasis is how the body ensures that we meet our needs: when we are hungry, we eat, when we are sated, we stop eating. Everyone’s eating should be pretty balanced: no overeating, undereating, or inappropriate weight. Unfortunately, a little too simple…
Hunger =/= Satiety

Question 29

Why are there difficulites with the balance sometimes?

Answer 29

Homeostasis is a baseline for explaining eating behaviours. There are multiple factors that we need to understand. It mattters becuase of the health implications of normative poor eating

Question 30

What are the health implication of poor eating?

Dutch hunger winter 1940

Answer 30

Horrible winter with no supplies
Victims of hunger winter studied

Question 31

What are the health implication of poor eating?

Minnesota starvation experiment (Keys et al 1950)

Answer 31

Join the army or take part in a starvation experiment (concerns around coercion). Studied the effects of starvation on 35 men. Cognitive, socially, emotional effects of starvation and weight gain

Question 32

What are the deficits that might come from poor eating?

Answer 32

Nutritional deficits e.g., scurvy; rickets; Korsakoff’s syndrome.

Starvation effects can be immediate, long-term or both: concentration/cognitive, social, physical and mental development, emotional instability (tryptophan cycle) and all physical systems.

Starvation effects can cross generations e.g., obesity in the children of starved mothers.

Question 33

What are some implications of poor eating?

Answer 33

Obesity affects multiple systems, including social functioning. Strong link to premature mortality. Also related to specific problems in children:
-experiences of bullying
-school absence
-stigma
-self-esteem

Question 34

What are some factors that take use away from homestasis?

Answer 34

Genetics
Learning
Social learning
Social pressures
Food industry
The ‘toxic environment’

Question 35

What is a genetic/evolutionary factor?

Answer 35

Genetic factors make us more likely to eat particular foods. We can learn other tastes, but it takes longer: commonly referred to as ‘grown-up’ tastes (olives, acid foods, etc.).
We are predisposed to high-energy, high-taste foods in the following categories, as they are more likely to contain nutrients
* sweet
* Fatty
* Salty
We are less likely to enjoy bitter foods, as they are more likely to be associated with toxicity

Question 36

What influences learned taste prrefernces adn aversions?

Answer 36

Culture: foods can be common in one culture but rare in another

Upbringing: foods experienced early tend to be more readily approached

Satiety to specific foods e.g., “I don’t want curry again. We just had it last night.” helps to keep our diet varied

Question 37

How does social learning affect eating/hunger?

Answer 37

Social/observational learning means that we eat in a number of ways that are influenced by what we see going on around us. Imitation of what and how others eat:
* types of food
* specific foods
* speed of eating
* amount eaten
This can be a very powerful cultural influence: people tend to eat what they see as normal/local/customary

Question 38

What are some envionmental factors?

Answer 38

Lighting: we eat more in dim lighting
Temperature: we eat more when cold, less when hot
Portion sizes: what is portrayed as ‘normal’?
Smells: of the food, and of the environment itself
Location/proximity of foods

Question 39

How does the agriculture adn food industry affect food intake?

Answer 39

The food industry goes through stages in its level of positive/toxic influence. Ensuring that we were not starved due to increasing population. ( the Malthusian hypothesis). Selling processed food that is relatively cheap: in large quantities, to ensure profit margins and fatty and sugary foods
Premium prices on more ‘healthy’ foods, often out of season, which is a ‘no-no’ in marketing terms

Question 40

How is High fructose corn syrup an exmaple of argriculer and food industry influences?

Answer 40

High fructose corn syrup (HFCS) became a huge product in the US in the 1970’s. Farmers subsidised to grow corn, but the government needed to do something with all that corn. Created a market for high fructose corn syrup. Supplied cheap for use in products (sugar in everything). Related to obesity levels.
HFCS has some unwanted side effects: fatty liver, decreased insulin sensitivity, gout precursors

Question 41

What was super-size me spurlock?

2004

Answer 41

Aim to draw attention to only meal options at McDonalds (& other fast food outlets) at the time were high calorie foods. Regular, Medium, Large & “Supersize” Options (advertising push by McDonalds).
If staff offered it, he had to take the ‘Super Size’ option. In 30 days, he gained 11kg, had scary cholesterol, mood swings, liver problems. The liver effects were most surprising. Significant negative publicity. Supersize option was withdrawn and salads, wraps and fruit introduced

Although, it drew a spotlight to marketing large portions and introducing greater within-restaurant choice.
It was subsequently revealed Spurlock had a significant alcohol problem which may have also contributed to the liver function issues documented in the film.