Energy Intake Flashcards
respiratory quotient
- how can it be used
- when can this come into play in disease
- vCO2/vO2
- each macronutrient is associated with a different value
- used as an indicator of the relative proportion of macronutrient being oxidized
- comes into play when a disease state effects the proportion of O2 to CO2 such as pulmonary diseases that result in CO2 retention
three components of total energy expenditure (TEE)
- basal energy expenditure (BEE), accounts for about 2/3 of TEE
- thermic effect of feeding (TEF), usually about 10-15%
- expenditure of physical activity (EEPA), can be very variable due to differences in activity level and lifestyle (high exercise will decrease the contributions of BEE and TEF to TEE)
factors that contribute to BEE
- FFM (the most metabolically active tissues), most important determinant
- thyroid hormone, primary hormonal determination
- catecholamines and sympathetic
- aging, loss of muscle mass
- gender, differences in body comp after puberty
- uncoupling proteins
- illness, increased BEE
- medications and increase or decrease
TEF
- proportional to
- macronutrient differences
- is this an important contributor to TEE or body weight?
- proportional to food intake
- protein 20-30% of its energy
- carbs 5-10% of its energy
- fat 5% of its energy
- not an importatn contributor to TEE or body weight
EEPA
-components
- exercise
- non-exercise activity thermogenesis (NEAT): energy spent on the activities of daily living, posture, fidgeting, and other activities such as chewing
how is BEE measured
-indirect calorimetry, which is the measurement of vCO2 and vO2
short term homeostatic signals
- what do they regulate
- initiation of eating
- how much is eaten during a session
- duration between sessions
types of short term signals
- availability of glucose or free fatty acids in the brain
- gastric distention
- hunger and satieation hormones
long term homeostatic signals
- leptin and insulin
- directly related to fat storesor insulin resistance due to fat stores
non homeostatic signals
-result in reward an reinforcement of intake
-
reinforcement of food intake
- this occurs when post ingestive factors are paired with sensory properties
- this results in the pleasure of eating food
food factors that influence intake
- dietary fiber
- macronutrient composition
- glycemic index and glycemic load
- energy density
- liquid or solid
- availability
- variety
- palatability
dietary fiber
- act to retain water in the stomach
- slow gastric emptying due to gel formation
- slow absorption and digestion in the small intestine
- triggers hormones such as GLP1
- fecal excretion of energy
macronutrient composition most likely to effect intake
-high protein low carb
glycemic index and glycemic load
-blood glucose response to food may influence later intake by its effects on insulin and therefore glucose
large and rapid increases in sinsulin
-proposed to result in overshoot of blood glucose and stimulate hunger
energy density
-the amount of energy per unit weight of food may underly some of the effects of high fat diets to promote excess food intake
availability of food
- can lead to a greater intake if the food is available in the immediate environment
- portion size also falls under this
variety
-increasing variety of a type of food or increasing more types of food leads to greater intake
ghrelin
-the only known circulating hunger hormone
CCK
-stimulated by the duodenum in response to ingestion of protein and fat and leads to satiation via the CNS
glucagon like peptide
- GLP1
- stimulated by the presence of macronutrients in the small intestine and leads to delayed gastric emptying and satiety via the CNS
leptin
- reflects what
- production
- fucntion
- action
- obese people
- mutations
- reflective of the bodies fat stores
- protein that is produced in fat cells in proportion to stored fad and secreted into circulation
- crosses blood brain barrier and acts on the hypothalamus to decrease food intake
- concentration in obese people is proportional to their body fat but this impairs the function of the hormone (resistant)
- mutations in the hormone itself are rare but there are mutations found in the melanocortinin receptor responsible for its signaling
- injection in deficient individuals fixes obesity
- injections have a very modest effect in people who are not deficient
