chapter fourteen

path of the digestive system

mouth to stomach to small intestine to large intestine

what does the mouth do during digestion

mix food with enzymes

what does the stomach do during digestion

mix food with gastric juices and break it down

what does the small intestine do during digestion

absorb necessary nutrients

what does the large intestine do during digestion

reabsorb left over water

how much of food is available for use (metabolized)

75%

how is food broken up in your metabolism

8% is processing, 55% to the basal metabolism, and 12% for activity

what happens during the 8%

metabolic rate and heat will rise

what is the basal metabolism (55%)

it’s energy to maintain life-sustaining processes

what do you target when you want to change body weight

basal metabolism

what kind of activity is the 12%

movement and behavioral processes

processing food will stay the same, but how many calories to take in…

can alter between basal metabolism and activity

when does stable weight occur

when energy intake (calories) is equal to energy output (basal and activity)

who, when, and why did they conduct experimental starvation

ancel keys in 1940; to look at effects when weight was reduced by 25%

personality wise what happened to the starvation victims

initially optimistic but became irritable, apathetic, and lost joy in daily activities, obsessed with thoughts of food

what were the thoughts on speed of re-feeding

angry; they thought it was too slow

when the participants stayed for six months…

they reached 75%

energy expenditure is…

adjusted in response to nutrition

when you use caloric restriction to decrease body weight…

caloric restriction will have greater impact on metabolism then weight

why doesn’t calorie restriction always work

your body fights back

what was the yo-yo experiment

1986 lab rats; learned wherever you are is what your body will consider normal and try to maintain

what was phase one in the yo-yo experiment

rats were fed high calorie diets until obese, then restricted diet to bring them to normal weight

how long did it take for rats to return to normal in phase one

46 days to get them obese, and 21 days to get back to normal

what was phase two of the yo-yo experiment

same process as phase one

what was the result of phase two (yo-yo experiment)

14 days to become obese, 46 days back to normal weight

what was the moral of the yo-yo experiment

once you restrict calories after obesity, your body works more efficiently

what helps set homeostatis

metabolism and energy

what’s the deal with metabolism and mice

people genetically engineered mice to use more energy, and their set point changed (they can eat more than normal and still weigh less)

benefits of calorie restriction (for your life)

increases life expectancy (modestly)

where, who and what was the experimental overeating

vermont state prison, prisoners, and goal was to gain 20/30 pounds

facts about weight in the vermont experiment

most prisoners returned to normal body weight, but the rate of loosing differed

what was the relationship with food with the prisoner that had to eat 10,000 calories a day

food became repulsive

what is homeostasis

process of maintaining a relatively stable internal environment

set zone is…

more accurate than a set point

what is the basic principle for homeostasis

redundancy (allows us to resist change and defend weight); there are multiple systems to make you eat or make you stop

what is the neural control of satiety and hunger

a duel-center hypothesis in the hypothalamus

what are the two appetite centers in the hypothalamus

ventromedial and lateral hypothalamus

what is the deal with the ventromedial hypothalamus (vmh)

when you remove this, their set point for satisfaction changes

what is the deal with the lateral hypothalamus

when you lesion this, people stop eating and become aphasic because their set point for body weight was lowered

the more you destroy… (setpoint)

the lower the set point will be

neural signals for satiety and hunger

insulin, ghrelin, leptin, pyy 3-36, and glp-1

what is insulin

stimulates eating behavior when levels are high or low

what is pyy 3-36

suppresses appetite; secreted by ileum and colon

where is your ileum

bottom of small intestine

what is ghrelin

appetite stimulant that rises during fasting; secreted by stomach and top of intestine

what part of the hypothalamus deals with pyy and ghrelin

the arcuate nucleus of hypothalamus

relationship between ghrelin and obesity

sometimes levels remain high after eating (when they should go down) therefore they will continue to eat

what is glp-1 (consumption)

released during consumption to slow down gastric emptying and counteract ghrelin; secreted from ileum and colon

process of glp-1

enters circulation, passes through blood-brain barrier to arcuate nucleus; decreases appetite and feeding behavior making food less rewarding

which neural signal is the most effective weight loss strategy

glp-1

what is the active ingredient in ozempic

glucagon-like peptide that mimic glp1; originally designed to treat type one diabetes

what does “big-boned” mean

people carry more muscle or fat; amount is hard to estimate without scanning technique

excess energy is stored…

as fat; enhances survival if food is scarce

what happens when you’re starving (glucose-dependent)

body will break down and dispose tissue which gives out glucose and ketones

what did overweightness use to signify

wealth, prosperity, and beauty

what percentage of adults are considered obese

40%

what states are at the top of obesity bmi index (epidemic)

mississippi and west virginia

where does the idea of bmi and obesity epidemic come from

the 1980+ environment; people believed we were eating too many fats so they were replaced with carbs

parental obesity may program metabolic disadvantages in offspring by…

epigenetic transmission

what is an epigenome

network of chemical compounds that surround dna and play a role in what genes are expressed, but don’t alter the sequences

moral of epigenetics and parental obesity is…

altering gene expression without altering the information

what do they mean by a thrifty metabolism

wanting to consume less and still being able to function

what’s the deal with the ob mice

those that had the gene couldn’t detect or produce leptin so they ate larger amounts

did the ob gene experiment (and leptin) work on humans

no; obese people produce leptin and do it at a higher rate

what do hormones work and rely on

negative feedback

what is leptin

a tracker of fat storage; secreted by fat cells in the arcuate nuclei and regulated by ob gene

what else does leptin do

signal suppression of production and release neuropeptide y

what does neuropeptide y do

stimulates eating in absence of leptin

what was the surgical squirrel experiment

gave them lyposuction; but regulation was so precise that after surgery they gained weight back

what are the three surgical procedures to reduce calories

sleeve gastrectomy, gastrointestinal bypass, and gut liner

what is a sleeve gastrectomy

removing portion of the stomach (where ghrelin is released), decreasing absorption

what is a gastrointestinal bypass

bypassing a big portion of the stomach; decreasing amount of absorption

what is a gut liner

less invasive surgery in small intestine that prevents absorption of nutrients

things that are included in mortality risk of obesity

type two diabetes, cardiovascular disease, osteoarthritis, and high blood pressure

what shape is the relationship between health and weight

u shaped

who are most at risk for mortality in weight

the thinnest and the heaviest

bmi for moderate obesity

25 - 32

bmi for obese

32 - 36

bmi for grossly obese

36-40

bmi for morbidly obese

40>

risks for obese men

moderately risk of zero, then 1.3, 1.9, and 3.1

risks in obese women

moderately risk of 1.1, then 1.2, 1.3, and 2.3

difference between fat in belly compared to other places

fat in belly means you’re more associated to risks than thighs or hips

true or false: distribution of fat is associated with risk

true

what is beer belly

a metabolic syndrome; causes increased risk of high blood pressure, cardiovascular disease, and type two diabetes

people classified as obese spend…

2,000 dollars more on medical care than those not

what is the best predictor of obesity in adulthood

obesity in adolescence

what is anorexia nervosa

intentional self-starvation for purpose of dramatic weight loss; even after loss they may continue to see themselves as overweight

what are the two purposes of excessive exercise for anorexia

facilitate weight loss and curb appetite

things that regurgitation can cause

tooth decay, paused mensuration, osteoperosis, widening of sulci in the cortex

relationship with anorexia and food

they’re interested in food just won’t eat it; insulin is still being secreted

facts about anorexia

highest mortality rate and difficult to treat due to a mix of genetics, endocrine, personality, cognitive, and environmental variables

statistics for anorexia

30% will die and 75% will recover

what is bulimia nervosa

eating vast quantities of food and then purges; feeling of no control over eating

what are the damages of bulimia

teeth rotting, hypoglycemia, anemia, and potential damage to mouth and esophagus

treatment for bulimia

ssris

what is binge eating disorder

uncontrollable intake of food far beyond what is required at least once a month for three weeks with feeling of no control

qualities of binge eating

no purging, and most who struggle with this are obese but don’t see weight as an issue

treatment for binge eating

prozac (ssris)