Regulation of Appetite and Body weight Flashcards
Thermodynamic model of energy balance (what is it)
Define (in the context of the model): weight gain, weight loss
Energy storage/balance: difference between energy coming in and energy going out
Weight gain: in > out
Weight loss: out > in; in < out
Long term changes are more sustained, daily changes are variable
Components of energy intake
What impacts nutrient availability?
Energy content of major foods
Main component of energy intake is the digestible energy
What we get out of food depends on how it’s been cooked (raw prolly got more nutrients) and gut factors (things like surgery)
Energy content of most foods: carbs, proteins, fats, alcohol
Components of energy output
REE (resting energy expenditure)
NREE (non resting energy expenditure)
TEF (thermodynamic effect of food)
Resting energy expenditure definition
When is the value collected for a test?
Depends on __? What’s the strongest determinant of REE?
Why is REE higher in obese pts?
(usually collected following an overnight fast)
Energy required at rest to carry out essential functions (about 60-70% of total Eo); used for heat generation, maintaining essential functions (e.g. breathing, heart beating etc)
Depends a lot on body composition
Fat free mass/lean muscle mass – strongest determinant of REE (higher in obese pts because they have greater NET mass, (FFM + fat mass, but I don’t understand how obese individuals can have a more FFM??)
Brown adipose tissue, being the more metabolically active fat may also contribute to REE
Non resting energy expenditure
Definition (+ what % of Eo)
exercise vs non exercise activity thermogenesis
Non resting energy expenditure (energy used when you’re doing stuff); 20 - 30% of Eo
exercise activity thermogenesis: intentional movement
Exercise can impact REE for up to 24 hours, may be a feed forward effect, depends on exercise intensity**
Non exercise = standing, shivering, movement that’s not at the level of exercise
Thermic effect of food (TEF)
What is it, what % of Eo and what does it depend on?
Thermic effect of food: energy required to digest food we eat (10% of Eo)
protein requires more energy to digest compared to carbs or fat
Components of stored energy
Triglycerides
Protein
Glycogen
Triglycerides
T/F: they’re the major fuel reserve of the body and have a potentially unlimited capacity
What happens to adipocytes as we gain weight?
Associate w/ water or naw?
True dat; Most energy formed as triglycerides
As we gain weight, our adipocytes get larger and increase in number
Them are hydrophobic so naw
Proteins
Where are they stored? What are they manily used for?
Associate w/ water or naw?
Proteins: stored in muscle, mainly for structural purposes
aa’s can be used for energy if we’re depleted;
Kinda but apparently at a lower volume/gram than carbohydrates
Glycogen
Why’s it efficient at storing energy? Hydrophilic or naw?
What’s the capacity (finite or unlimited and why?)
What’s the capacity in liver vs muscle? T/F: trained athletes can double their capacity
Glycogen – very hydrophilic;
Efficient energy storage b/c its branched chains so that allows for quick cleavage of glucose moieties
Capacity is finite (less than one day’s worth of glycogen storage) because it traps a ton of water; liver = 120grams/500kcal; muscle = 400 grams/1600 kcal; trained athletes can apparently double this
Weight loss is usually loss of what kinda weight?
Long term weight loss is loss of what?
Changes in body weight = changes in water weight usually;
long term – changes in adipocyte/fat mass
Energy storage is net __ from conception onwards
Energy needs of babies vs adults
Temporal changes in stored energy:
What happens over 24 hrs (net positive/negative?)
Changes to body mass (do you maintain constant, does it vary, what does age have to do with anything?)
From conception onwards, energy storage is net positive
Babies have larger Ei compared to Eo coz they’re growing (baby = 50-60 kcal; infant/child = 80-110 kcal)
Avg adult intake = 30ish kcal/day
In 24 hr period, you’ll be net positive; energy balance is only when averaged over time
In general, you maintain a constant body mass
With aging, you lose muscle mass and gain fat mass
Changes in body mass also trigger changes in energy expenditure
What is this concept of adaptive thermogenesis?
Adaptive thermogenesis: change in energy expenditure that’s observed with change in weight; observed change in energy expenditure is out of proportion to change in weight (there’s about a 400-500 calorie difference in energy expenditure)
BMI calculation (metric and US)
BMI classifications
BMI: proportion of weight to height
Set point hypothesis
How does this hypothesis explain what happens with obese patients?
Body is programmed to function optimally within a certain range and it uses active mechanisms to control that
There might be some dysfunction/dysregulation in the system
Relationship between leptin and fat mass. This is suggestive of what problem that explains why leptin replacement doesn’t work for weight loss in obese patients?
There’s a linear relationship between increasing BMI (therefore increasing adipose tissue) and leptin levels
There’s probably some leptin resistance; obese pts were given leptin replacement; it didn’t help with weight loss
what’s the whole idea of the satiety cascade?
factors that will impact satiety (basically 3 big categories)
Over time, satiety levels are decreasing after having eaten a meal
Meal quality, meal quantity, nutrition status
Brown fat locations
(Chimdiya would massage Matthew’s __ w/ a blade; the other name for your collar bone; biggest artery in body and where it sits on; location of adrenal gland (ie what else was it called?))
Neck
Supraclavicular
Para aortic
Para vertebral
Suprarenal
