weight management Flashcards
define body weight
the sum of bone, muscle, organs, body fluids and adipose tissue
some or all components of body weight are subject to normal variation and change resulting from:
(4)
- growth
- reproductive stress
- variation in physical activity
- effects of aging
consistency in body weight is orchestrated by:
(4)
- neural mechanisms
- hormonal mechanisms
- chemical machanisms
- individual genetic polymorphisms
define fat mass
fat from all body sources including the brain, skeleton and adipose tissue
define fat-free mass
includes water, protein and mineral components
proportions of _ mass are relatively constant from person to person
fat-free mass
lean body mass is muscle that
(4)
- is higher in men than women
- increases with exercise
- is lower in older adults
- is a major determinent of resting metabolic rate (RMR)
adjusted body weight calculation
(actual body weight - ideal body weight (Healthy BMI)) x 0.25 + ideal body weight
what is body fat a combination of?
combo of essential and storage fats
- that are expressed together as a percent total body weight
why is essential fat necessary and where is it stored?
- necessary for normal physiologic functioning
- stored in small amounts in the bone marrow, heart, lung, liver, spleen, kidneys, muscles and nervous system
what is storage fat and where is it stored?
- it is the energy reserve
- it accumulates under the skin and around the internal organs to protect them from trauma
- most is expendable
what are the averages of total body fat for men and women
men: 18-24% of total body weight
women: 25 - 31% of total body weight
what does adipose tissue influence and where is it primarily located?
adipose tissue exerts a profound influence on homeostasis
located primarily:
- under the skin
- in the mesenteries
- in the omentum
- behind the peritoneum
what is white adipose tissue?
it stores energy as a repository for triglycerides
- cushions abdominal organs
- insulates the body to preserve heat
what is brown adipose tissue?
- mainly located in scapular and subscapular areas
- made up of small droplets and many more ion-containing mitochondria - which makes its appear brown
- activated from cold exposure to regulate body temp
what do mature adipocytes consist of?
a large central lipid droplet surrounded by a thin rim of cytoplasm, containing the nucleus and the mitochondria
cells can store fat equal to ~-~% of their volume.
90-95%
what is hyperplasia?
increasing the number of cells
what is hypertrophy?
increasing the size of existing cells (as liipid is added)
increases in fat cell size are more common in _ and _ but cell number can _ after the fat content of existing cells has reached capacity
teens and adults
increase
most deposited fat comes directly from _
dietary triglycerides
the fatty acid composition of the adipose tissue mirrors the fatty acid composition of the _
diet
excess dietary carbohydrates and protein are converted to _ in the liver via _
fatty acids
lipogenesis
under normal conditions, little dietary carbohydrate is converted to _
- the conversion process requires _x more energy than is required to store dietary fat as fat
fatty acids
3x
semivolatile organic compounds accumulate in adipose tissues from exposure to:
- toxins
- chemicals
- pesticides
these are released when adipose tissue is mobilized during wt loss
dont encourage women of higher weight to lose it during pregnancy (toxins, pesticides, chemical released into blood which could go to the fetus and we dont know what the result of that is)
what is lipoprotein lipase?
an enzyme that moves lipid from the blood into the adipose cell, by hydrolyzing TGs into FAs and glyceryol
- glycerol goes to the liver
- FAs enter the adipocyte and are re-esterified into TGs
body weight is a product of:
- genetic effects
- epigenetics effects
- the environment
body weight regulation is often described as a homeostatic biological feedback system designed to “____” a stable blody weight
- regardless of energy ____ or energy ____
- is, unfortunately, assymetric in that it more vigorously _ weight loss than weight gain
Body weight regulation is often described as a homeostatic biological feedback system designed to “defend” a stable body weight
- Regardless of energy expenditure or energy intake
- Is, unfortunately, asymmetric in that it more vigorously defends weight loss than weight gain
what is known about body weight regulation is in the realm of _ regulation
appetite
adaptation to energy restriction is well known but highly _
unpredictable
satiety is associated with….
satiety is associted with the state, after eating, during which excess calories and nutrients are being stored
hunger is present when….
hunger is present when the satiety stores are being stored
hunger triggers are much _ than indicators of satiety
stronger
external cues for eating can easily override _
satiety
children are more able to eat less or more when _ or _ occurs
overfeeding or underfeeding
adults are less able to compensate for overeating over time, which leads to …
gradual elevation of weight over time
resting matabolic rate (RMR) explains _____ -_____% of total energy expenditure
60-70%
RMR declines with…
age
restriction of energy intake
when the body is deprived of adequate energy, the body conserves energy by dropping RMR as rapidly as _% in weeks
15%
what is activity thermogenesis?
activity termogenesis is energy expended in voluntary activity
- most variable component of energy expenditure
under normal circumstances activity thermogensis accounts for ____ - ____% total energy expenditure
~15-30%
nonexercise activity thermogensis (NEAT) is energy expended for all activity that is …
NOT sleeping, eating, or sports-like exercise
going to work, typing, doing yard work, fidgeting
NEAT varies as much as _kcal/day between individuals
2000 kcal
to reverse obesity, promote….
standing and ambulating for 2.5 hours/day and reengineer work, school, home environments to support a more active lifestyle
what does insulin do to affect weight
insulin controls the amount of glucose in the blood by moving it into the cells for energy
how does the hormone leptin affect body weight
leptin contributes to long-term fullness by sensing the bodys overall energy stores
how does the hormone adiponectin affect body weight
adiponectin is made by fat cells, it helps the body respond better to insulin by boosting metabolism
how does the hormone ghrelin affect body weight
ghrelin tells the brain when the stomach is empty, prompting:
- hunger pangs
- drop in metabolism
the stomach communicates with the brain via the _ nerve, which travels from the _ to the _
Stomach communicates with the brain via the vagus nerve, which travels from the brain to the stomach
when full, the stomachs _ _ sends a message to the brain indicating satiety
stretch receptors
what factors of weight are influenced by genes?
number and size of fat cells, regional distribution of body fat and resting metabolic rate
what can activate or deactivate obesity-triggering genes?
nutrition and/or lifestyle
classes of drugs known to lead to weight gain
6
- diabetes medications (glyburide)
- thyroid hormone replacement (synthroid)
- psychotropics (olanzapine)
- antidepressants (aripiprazole)
- steroids (predisone)
- antihypertensives (beta blockers)
shortned sleep alters _ regulation of both hunger and appetite
endocrine
recurrent sleep deprivation can modify the _, _ and _ of food intake
amount, composition and distribution
stress stimulates the release of _
cortisol
cortisol stimulates the release of _ to maintain blood glucose levels
insulin
- this leads to increased appetite
chronic stress with constantly elevated cortisol levels can leave to _ changes
appetite
cortisol is normally _ in early morning and _ around midnight
high / low
those with night-eating syndrome have delayed circadian rhythm related to genetic factors that alter _ levels
cortisol
what is sensory specific satiety?
- as foods are consumed, they become less desirable, so people eat more when offered a variety of choices than when a single food is available
what is a benefit of sensory-specific satiety
the benefit is that this inclination encourages intake of a varied and nutritionally balanced diet
what is the negative of sensory specific satiety?
it can lead to overconsumption