Energy Intake

Question 1

respiratory quotient

• how can it be used
• when can this come into play in disease

Answer 1

• 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

Question 2

three components of total energy expenditure (TEE)

Answer 2

• 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)

Question 3

factors that contribute to BEE

Answer 3

• 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

Question 4

TEF

• proportional to
• macronutrient differences
• is this an important contributor to TEE or body weight?

Answer 4

• 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

Question 5

EEPA

-components

Answer 5

• exercise
• non-exercise activity thermogenesis (NEAT): energy spent on the activities of daily living, posture, fidgeting, and other activities such as chewing

Question 6

how is BEE measured

Answer 6

-indirect calorimetry, which is the measurement of vCO2 and vO2

Question 7

short term homeostatic signals

- what do they regulate

Answer 7

• initiation of eating
• how much is eaten during a session
• duration between sessions

Question 8

types of short term signals

Answer 8

• availability of glucose or free fatty acids in the brain
• gastric distention
• hunger and satieation hormones

Question 9

long term homeostatic signals

Answer 9

• leptin and insulin

- directly related to fat storesor insulin resistance due to fat stores

Question 10

non homeostatic signals

Answer 10

-result in reward an reinforcement of intake

-

Question 11

reinforcement of food intake

Answer 11

• this occurs when post ingestive factors are paired with sensory properties
• this results in the pleasure of eating food

Question 12

food factors that influence intake

Answer 12

• dietary fiber
• macronutrient composition
• glycemic index and glycemic load
• energy density
• liquid or solid
• availability
• variety
• palatability

Question 13

dietary fiber

Answer 13

• 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

Question 14

macronutrient composition most likely to effect intake

Answer 14

-high protein low carb

Question 15

glycemic index and glycemic load

Answer 15

-blood glucose response to food may influence later intake by its effects on insulin and therefore glucose

Question 16

large and rapid increases in sinsulin

Answer 16

-proposed to result in overshoot of blood glucose and stimulate hunger

Question 17

energy density

Answer 17

-the amount of energy per unit weight of food may underly some of the effects of high fat diets to promote excess food intake

Question 18

availability of food

Answer 18

• can lead to a greater intake if the food is available in the immediate environment
• portion size also falls under this

Question 19

variety

Answer 19

-increasing variety of a type of food or increasing more types of food leads to greater intake

Question 20

ghrelin

Answer 20

-the only known circulating hunger hormone

Question 21

CCK

Answer 21

-stimulated by the duodenum in response to ingestion of protein and fat and leads to satiation via the CNS

Question 22

glucagon like peptide

Answer 22

• GLP1
• stimulated by the presence of macronutrients in the small intestine and leads to delayed gastric emptying and satiety via the CNS

Question 23

leptin

• reflects what
• production
• fucntion
• action
• obese people
• mutations

Answer 23

• 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