Energy balance

Question 1

3 types of energies

Answer 1

1. heat
2. mechanical
3. electrical

Question 2

3 components of energy expenditure + %

Answer 2

1. Basal metabolism (50-65%): activities that keep body functioning
2. Thermic effect of food (5-10%): body’s metabolic response to food
3. Physical activities (25-50%)

Question 3

Factors that affect BMR. What raises BMR? What lowers it?

Answer 3

age, height, growth, body composition
Raises BMR: fever and stress, smoking, caffeine, hormones, more lean tissue
Lowers BMR: fasting/starvation, malnutrition, hormones, sleep

Question 4

How to calculate BMR? Formula + have to be: (6). if conditions not met?

Answer 4

Indirect calorimetry through respiratory gas exchange. CO2/O2
Have to be: completely relaxed, reclining, awake, thermoneutral, fasted, no PA for last 12 hours
If not met: Resting Metabolic Rate

Question 5

1 lb of fat = _____ kcal?

Answer 5

3500 kcal

Question 6

454 g fat in body –> ___% is fat

Answer 6

87%

Question 7

How much error in EER? less accurate for who?

Answer 7

20% –> plus or minus 10%
elderly and ethnic groups

Question 8

Physical activity VS Physical activity level –> which is used in formula for EER? what are the ranges?

Answer 8

PA is used:
Sedentary: 1.00
Low active (30-60min): 1.11-1.12
Active (at least 60min): 1.25-1.27
Very Active (2-4h per day): 1.48-1.45

Question 9

Hunger = ______ influences
Caused by (5)
Hunger definition

Answer 9

physiological influences
- caused by empty stomach, gastric contractions, absence of nutrients in small intestine, GI hormones, endorphins triggered by smell/sight/taste/food
- irritating feeling when energy is low

Question 10

2nd step of food intake (after hunger) + what influences?

Answer 10

Seeking food and starting a meal
- sensory influences: thought, sight, smell, sound, taste

Question 11

3rd step of food: what influences? (6)

Answer 11

cognitive influences
- presence of others, social stimulation, perception of hunger, favorite foods, time of day, abundance of food

Question 12

Satiation = when? + what influences? + what happens
Satiation definition?

Answer 12

• end of meal, when food enters digestive tract
• post-ingestive influences
  food in stomach triggers stretch receptors –> nutrients in small intestines elicit hormones (CCK which slows gastric emptying)
• satiation = short term feeling of fullness: tells you to stop eating

Question 13

Satiety: when? + what influences? + what happens?
Satiety definition

Answer 13

• several hours later, after nutrients enter blood
• post-absorptive influences: nutrients in blood signal brain about availability, use and storage –> as nutrients dwindle, satiety diminishes –> hunger develops
• satiety = long term feeling of fullness

Question 14

Appetite control: what governs regulation of appetite/eating?

Answer 14

the brain

Question 15

Homeostasis of hunger controlled by what?

Answer 15

Hypothalamus
givers hunger signal –> physiological –> gastric hormone

Question 16

Reward system controlled by what?

Answer 16

Dopamine system:
gives feeling of pleasure –> tends to be the most powerful of the 3

Question 17

Cognition controlled by what?

Answer 17

Prefrontal cortex and hippocampus: I know chocolate is not good –> eat apple instead

Question 18

Appetite = _________ hunger –> influenced by what?

Answer 18

psychological hunger –> not actually in need of food
- influenced by external environment and cues (seeing and smelling cinnabon)

Question 19

Leptin = ______ hormone –> tells you you’re ________
- made by _______ tissue + some produced in ________

Answer 19

satiety. tells you you’re full
- made by adipose tissue + some in stomach

Question 20

Negative feedback loop of leptin

Answer 20

gain in body fatness stimulates leptin production VS loss in body fatness suppresses leptin production

Question 21

High levels of leptin will (2)

Answer 21

1. tell brain that you have plenty of fat stored
2. act on hypothalamus to decrease food intake (increase satiation) + decrease body weight + increase energy expenditure

Question 22

Low levels of leptin will (2)

Answer 22

Tell your bain fat stores are low + you need to eat

Question 23

Can the body be desensitized to leptin?

Answer 23

Yes! leptin resistance

Question 24

Ghrelin = _______ hormone –> tells you you’re ________ –> what do they do?

Answer 24

Hunger hormone
tells you you’re hungry
- may help prepare for food intake by increasing gastric motility and gastric acid secretion

Question 25

Ghrelin regulation –> highest when and low when?

Answer 25

Highest before meal when hungry + return to low levels after mealtime

Question 26

What gives sensation of fullness? which nutrients + other characteristics?

Answer 26

Fat and protein –> slow stomach emptying = feeling of fullness
- protein = most satiating macro –> thermogenic + aa role in brain
- high in fiber, in water + puffed with air

Question 27

Healthy BMI? vs underweight? vs overweight vs obese?

Answer 27

healthy: 18.5-24.9
underweight: <18.5
overweight: 25-29.9
obese: >30

Question 28

Limitations of BMI (5)

Answer 28

1. doesn’t distinguish between body composition
2. focusses on weight
3. doesn’t say where fat is located
4. ethnicity differences
5. a lot more things influence health (exercise, diet…)
6. doesn’t tell you fitness level or proportion of lean/muscle mass

Question 29

Healthy body weight defined as weight that ______?

Answer 29

Does not increase risk of disease

Question 30

Subcutaneous vs visceral fat

Answer 30

Subcutaneous: most evident, below skin, pear body
Visceral: central obesity, surrounding organs = higher risk of disease –> apple android

Question 31

In general, women have __% more body fat than men at same BMI

Answer 31

12

Question 32

Health problems associated with overweight/obesity (7)

Answer 32

T2D, dyslipidemia, hypertension, coronary heart disease, gallbladder disease, obstructive sleep apnea, certain cancers

Question 33

Health problems associated with underweight (5)

Answer 33

undernutrition, osteoporosis, infertility, impaired immunocompetence, eating disorder

Question 34

Fat cell development: hyperplasia vs hypertrophy?

Answer 34

Hyperplasia: grow more in number
hypertrophy: increase in size

Question 35

Fat growth and fat loss schéma (4)

Answer 35

1. fat cells increase in number (hyperplasia)
2. when energy intake above expenditure: hypertrophy
3. if continues: fat cells may increase in number again
4. with fat loss, fat cells shrink but don’t decrease in number

Question 36

Lipoprotein lipase: what does it do?

Answer 36

Hydrolyzes triglycerides passing in bloodstream (in adipocytes and muscle) –> put them into cells

Question 37

How can Lipoprotein lipase affect people with obesity?

Answer 37

They might have more LPL and LPL that work more efficiently –> more difficult to lose weight

Question 38

Set point theory

Answer 38

Body strives to achieve homeostasis –> hypothalamus makes adjustments to return to set point.

Question 39

Yo-yo dieting (5)

Answer 39

Diet –> metabolism slows down –> end of diet –> normal eating (or more) –> weight gain –> repeat

Question 40

Physical activity can _______ metabolism and ___________ –> PA + diet = stronger effect to (3)

Answer 40

increase metabolism and energy out
- stronger effect to lose abdominal fat + retain more muscle + regain less weight