Hunger, eating and health Flashcards
how do the MOUTH and SALIVERY GLANDS process food?
mastication
saliva is alkaline
why is it good that saliva is alkaline?
balances out acidic stomach acids
stops stomach from eating itself
how does the OESOPHAGUS process food?
transport to stomach
alkaline conditions
how does the STOMACH process food?
peristalsis
breaks it down using acid digestive enzymes
how does the LIVER/GALL BLADDER process food?
additional digestive enzymes added into small intestine that allows food to start being absorbed
how does the PANCREAS process food?
produces insulin and glucagon to store and release energy
shifts glucose from blood to store as glycogen and protein (stores) =
insulin
shifts glycogen/proteins from storage glucose to fuel the body (releases) =
glucagon
what is used as fuel when glucose stores are low?
free fatty acids
how do the LIVER/KIDNEYS process food?
filter out toxins for excretion
in what ways is food processed differently in anorexia?
transit = slower, more likely to get constipated, once carb and fat stores are depleted the body uses up protein stores which depletes muscle
why is our food intake so complex?
- omnivorous
- diet includes range of elements that our bodies have evolved to process
- balance needed
- lots of variation between species and some variation within species
what is an example of variation of food within species?
dairy/gluten intolerance
what are the 3 core products from digestion?
- lipids(fats)
- amino acids(proteins)
- glucose(carbohydrates)
what are the 3 storage mechanisms?
fats
proteins
glycogen
mostly in the form of muscle tissue =
amino acids/proteins
largest and most efficient energy store =
lipids/fats
stored in muscles and liver as glycogen, fast release =
glucose
how do we know when to eat?
homeostasis/set point theory
hunger
cravings
hypothalamic regulatory nuclei in the brain are sensitive to what changes?
shortage of glucose
what organ is sensitive to shortages of glucose and lipids?
liver
what organ sends signals to the brain by releasing gherlin to ask for more food?
stomach
what 2 things to we experience when we are running low on fuel?
- hunger
2. cravings (this is when you are hypoglycaemic)
hunger is a _______ _____ due to low levels of fatty acids/glucose compared to cravings that is a more _______, ________ state
motivational state, automatic behavioural state
explain the set point theory
homeostasis balance > need to keep topping up our fuel level as we constantly burn it off
how do we know when to stop eating?
body generates range of short term SATIETY signals
what does satiety mean?
feeling of fullness
list some satiety signals the body gives to tell you to stop eating
- adequate glucose/lipid levels detected in brain and liver
- stomach distension
- buccal activity(lots of chewing)
- high levels of sensory stimulation
- appetite suppressant chemicals (caffeine, amphetamines)
what area of the brain was previously suggested to be the centre for satiety?
hypothalamus
more recent evidence suggests no such centre > process is more hormone controlled
what hormones are suggested to control satiety?
gherlin
neuropeptide Y
serotonin
what hormone do fat tissues secrete?
leptin
what are the effects of leptin?
increases metabolic rate and decreases food intake but desensitising brain to hunger signals and inhibits hormones that drive eating (particularly Neuropeptide Y) STOPS YOU EATING BASICALLY
what are the different components of the satiety cascade?
sensory > cognitive > post ingestive > post absorptive
what 2 things compete?
hunger and satiety
explain why everyones eating should in theory be balanced?
when we are hungry we eat and when we are sated we stop eating
why does eating go wrong for some people?
internal factors (learning, emotions)
toxic environment
homeostasis
what are some health implications of poor eating?
nutritional deficits effects of starvation (cognitive, social, physical and mental development) lack of concentration emotional instability all physical systems
how does lack of food effect emotion?
tryptophan cycle > tryptophan breaks down into serotonin (this doesn’t happen if insufficient supply)
can starvation effects cross generations?
yes, obesity seen in children of starved mothers
obesity has a strong link to?
premature mortality (death)
what specific problems does obesity cause in children?
bullying
school absence
stigmatisation
self esteem
what factors cause us to lose homeostasis of eating (knock us out of balance)?
genetics learning social learning social pressures food industry toxic environment
what tastes are we predisposed to preferring and why?
sweet, fatty, salty food categories as more likely to contain nutrients
why are we less likely to enjoy bitter foods?
associated with toxicity
what are learnt taste preferences and aversions influenced by?
culture
upbringing
satiety to specific foods (having something recently so want something different - keeps diets varied)
how does social learning affect the amount we eat?
influenced by what is going on around us
imitate what and how others eat
amount eaten, speed of eating etc
what are some environmental factors that affect eating?
- lighting (eat more in dim light)
- temp (eat more when its cold)
- portion sizes
- smells of food
- location/proximity of food
positive influence in early days where food industry ensured we were not starved due to increasing population = what hypothesis?
Malthusian hypothesis
give an example of negative impact from food industry
HFCS (high fructose corn syrup) huge product in 70s in US > farmers made to grow more corn > excess amount turned into sugar > created market > sugar in everything
what are the unwanted side effects of HFCS?
fatty liver
decreased insulin sensitivity
gout precursors
describe the toxic environment
where food is scarce obesity is a status symbol compared to where food is plentiful obesity is stigmatised, we have evolved to grab food where we can, industry sells bad food cheap and good food is expensive, less exercise and more time on screens, adverts for food everywhere, social events at food places, food delivery
the toxic environment has been happening long enough that we are now seeing ________ effects
intergenerational
what does the toxic environment model show?
how the imbalance of homeostasis and external factors can have a huge impact on health
