PSY333H5 Chapter Notes - Chapter 5: Polyphagia, Glucocorticoid, Adrenocorticotropic Hormone
PSY333 CHAPTER 5 – ULCERS, THE RUNS, AND HOT FUDGE SUNDAES
Stress and Food Consumption
- Stress makes 2/3 of people hyperphagic (eat more)
- And the rest hypophagic (eat less)
- During stressor
o Appetite and energy storage suppressed, and stored energy mobilized
- Post-stress period
o Reverse the processes
▪ Block the energy mobilization, store nutrients in bloodstream, and get more of them
▪ Appetite goes up
- CRH released by hypothalamus
o Stimulating pituitary to release ACTH
o Adrenal release of glucocorticoids
- CRH
o Helps to turn on SNS
▪ Increases vigilance and arousal during stress
▪ Suppresses appetite
- Glucocorticoids
o Stimulate appetite
▪ Stimulate it preferentially for foods that are starchy, sugary, or full of fat
- Timing is crucial
o When stressful even occurs
▪ Burst of CRH secretion within seconds
▪ ACTH levels take about fifteen seconds to go up
▪ Many minutes for glucocorticoid levels to go up in bloodstream
• CRH is the fastest/glucocorticoids are the slowest
o When stressful event is over
▪ Takes seconds for CRH to be cleared from bloodstream
▪ Can take hours for glucocorticoids to be cleared
o Large amount of CRH, yet almost no glucocorticoids
▪ Probably in the first few minutes of a stressful event
o Large amounts of CRH and glucocorticoids
▪ Middle of a sustained stressor
• Good time to have appetite suppressed
o Can only pull this off if appetite-suppressing effects of CRH are stronger
than appetite-stimulating effects of glucocorticoids
▪ (This is how it works)
o Substantial amounts of glucocorticoids in circulation but little CRH
▪ Recovery period
▪ Appetite is stimulated
▪ Glucocorticoids serve as the means of recovering from the stress-response
o Period where glucocorticoid levels are high and those of CRH are low is much longer than the
period of CRH levels being high
▪ Situation that winds up stimulating appetite
o Stressor lasts for days, nonstop
▪ Days of elevated CRH and glucocorticoids, followed by a few hours of high
glucocorticoids and low CRH, as the system recovers
• Situation results in suppression of appetite
- Type of stressor is key whether the net result is hyper- or hypophagia
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PSY333 CHAPTER 5 – ULCERS, THE RUNS, AND HOT FUDGE SUNDAES
o Frequent intermittent stressors
▪ On/off stressors
• Frequent bursts of CRH release throughout the day
• Elevated glucocorticoid levels are close to nonstop
o Stimulates appetite
▪ Westernized society → intermittent psychological stressors throughout the day
- How your body responds to a particular stressor also predicts hyper- or hypophagic
o Sources of individual differences can be psychological
o Differences can also arise from physiology
- Glucocorticoid hyper-secreters are the ones most likely to be hyperphagic after stress
o When individuals given array of foods to choose from during post-stress period, atypically crave
sweets
▪ Effect that is specific to stress
• People ho serete eess gluoortioids durig stress do’t eat a ore tha
the other subjects in the absence of stress and their resting non-stressed levels
of gluoortioids are’t a higher tha others
- Attitude towards eating also predicts hyper- or hypophagic
o Nutritional needs vs. emotional needs
▪ Emotional needs
• Overweight, stress-eaters
▪ Restrained eaters
• Eating is a regulated, disciplined task
• Actively trying to diet
• Not overweight
• Actively restricting their food intake
• During stress, people who are normally restrained eaters are more likely than
others to become hyperphagic
o Food becomes a coping device
Apples and Pears
- Glucocorticoids
o Increase the storage of the ingested food
▪ Trigger fat cells to make an enzyme that breaks down the circulating nutrients into their
storage forms
• Fat ells loated i our adoial area, aroud our ell; iseral fat
o Apple shape: fill up fat cells with fat, without depositing much fat
elsewhere in your body
o Pear shape: fat ells aroud our rear ed for gluteal fat
▪ Fill them up with fat, and you are pear shaped (round bottomed)
o Formal way to quantify different types of fat deposition:
▪ Measure circumference of waist (measures abdominal fat) and circumference of hips
(measures gluteal fat)
• Apples have waists that are bigger than hips, produig aist-hip ratio
o WHR that is bigger than 1.0
• Pears have hips that are bigger than waists
o WHR that is less than 1.0
- When glucocorticoids stimulate fat deposition, do it in the abdomen preferentially (promoting apple-
shaped obesity)
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