Unit 1; Nutrition & Energy Balance

Question 1

What are the two sides of the scale for energy balance?

Answer 1

Energy input vs energy output

Question 2

If energy output > energy input, what happens to weight?

Answer 2

Weight Loss (Negative balance)

Question 3

If energy input > energy output, what happens to weight?

Answer 3

Weight Gain (Positive balance)

Question 4

What other aspects, other than energy input & energy output, can add to the complexity of energy balance? Give 4 examples.

Answer 4

Genetics, psycho social, food availability, environmental factors

Question 5

Define Energy Input

Answer 5

The calories that our body needs that come from the food we eat.

Question 6

List the 3 types of macronutrients that are sources of energy.

Answer 6

Carbohydrates, proteins, fats.

Question 7

What other substance can also be an energy source and how many kcal/g does it contribute?

Answer 7

Alcohol = 7 kcal/g

Question 8

How many kcal/g do carbohydrates have?

Answer 8

4 kcal/g

Question 9

How many kcal/g do proteins have?

Answer 9

4 kcal/g

Question 10

How many kcal/g do fats have?

Answer 10

9 kcal/g

Question 11

How many calories per day is recommended for adults?

Answer 11

2000-3000

Question 12

What are 4 factors that can affect energy input?

Answer 12

Neuro-endocrine factors (neurotransmitters, hormones, etc), filling/distention of stomach (effects of dietary fibre), social/psychological factors (anxiety, depression), food availability & appeal

Question 13

Define Satiation/Satiety

Answer 13

Neural state that leads one to decrease or stop eating (loss of drive/desire to eat) [Occurs between meals]

Question 14

Define Hunger

Answer 14

Physiological drive to get food & eat

Question 15

Define Appetite

Answer 15

Psychological desire to eat (more conditional than hunger)

Question 16

How do neuro-endocrine factors influence energy intake?

Answer 16

Feeding behaviour, energy balance, & the production/secretion of hormones

Question 17

What hormones promote increased food intake?

Answer 17

Ghrelin, Neuropeptide Y (NPY/ NYP)

Question 18

What hormones promote decreased food intake?

Answer 18

Leptin, Peptide YY (PYY), Cholecystokinin (CCK), Apolioprotein A4 (apoA IV)

Question 19

What is the role of the hypothalamus in eating?

Answer 19

Central integrator of circulatory signals (hormones) & neural signals from other brain areas

Question 20

What is the role of leptin & where is it produced?

Answer 20

It is a satiety signal which is produced by the adypocytes (fat cells) & signals brain which in turn lowers NPY signals.

Question 21

What is the role of NPY & where is it produced?

Answer 21

Signals neurons to be more active which increases hunger signals and is produced in the brain.

Question 22

What is the role of Ghrelin & where is it produced?

Answer 22

Activates NPY system in turn increasing hunger and produced in stomach.

Question 23

What is the role of PYY & where is it produced?

Answer 23

Produced in the Gi tract in response to meal.

Question 24

What is the role of CCK & where is it produced?

Answer 24

Produced in Gi tract in response to meal.

Question 25

What is the role of apoA IV & where is it produced?

Answer 25

Produced in Gi tract in response to meal.

Question 26

What do the hormones do when food is consumed and digested?

Answer 26

When food is consumed & digested the gut is stimulated to produce PYY & CKK which contribute to satiety signals in the brain leading to decreased activity of NPY

Question 27

On the hormone level, what happens a couple hours after a meal?

Answer 27

Nutrients become stored in the fat cells (adipocytes), which increase secretion of leptin. Leptin signals to the hypothalamus to decrease activity of NPY reinforcing satiety.

Question 28

What happens in the body on a hormonal level when one is feeling hungry?

Answer 28

Ghrelin is secreted by the empty stomach (gastric & duodenal cells) which signals the hypothalamus to increase activity of NPY. After a long time without food consumption, the adipocytes greatly decrease their secretion of leptin.

Question 29

List the 3 ways that energy is used in the body (energy output).

Answer 29

Resting energy expenditure (REE), thermic effect of food (TEF), physical activity (PA).

Question 30

What is the approximate % total energy output for basal/resting energy expenditure?

Answer 30

65%

Question 31

Give examples of when your body uses a minimal amount of calories?

Answer 31

Awake, resting, fasting, & in warm, quiet low-stress environments

Question 32

Is REE or BEE easier to measure and why?

Answer 32

Resting energy expenditure (Only need to fast for 4 hours instead of 12hrs)

Question 33

What does BMR stand for?

Answer 33

Basal metabolic rate

Question 34

What does RMR stand for?

Answer 34

Resting metabolic rate

Question 35

What is the unit for BMR & RMR?

Answer 35

kcal/ kg body weight/ hour

Question 36

What period of time is BEE & REE measured over?

Answer 36

24hr period

Question 37

How does a greater body size affect REE?

Answer 37

Increases REE

Question 38

How does a greater proportion of lean body mass (more muscle) affect REE?

Answer 38

Increases REE

Question 39

How does older age affect REE?

Answer 39

Decreases REE

Question 40

How does gender affect REE?

Answer 40

Increased REE in men

Question 41

How does having higher thyroxine levels (thyroid hormone) affect REE?

Answer 41

Increased REE

Question 42

How does fasting affect REE?

Answer 42

Decreased REE

Question 43

How does a fever affect REE?

Answer 43

Increased REE

Question 44

How does pregnancy/lactation affect REE?

Answer 44

Increased REE

Question 45

How is % REE for each body system change for infants compared to adults?

Answer 45

Adults have an even % contribution to each body system (20% brain, 20% kidney & heart & adipose, 20% muscle, 20% liver, 20% other) compared to infants where the brain contributes a larger amount (44% brain, 15% kidney & heart & muscle, 15% liver, 25% other)

Question 46

What is the approximate % total energy output for thermic effect of food?

Answer 46

10%

Question 47

When is there an acute increase in energy expenditure due to the TEF?

Answer 47

After a meal

Question 48

What can influence the TEF energy expenditure?

Answer 48

Meal size, macronutrient composition, spices (mustard/peppers increase TEF of a meal by 10-30%)

Question 49

What is the relative ratio of TEF energy expenditure for each macronutrient?

Answer 49

1 fat: 1.5 carb: 3 protein

Question 50

What factor is associated w/ a lower TEF & why?

Answer 50

Obesity due to lower insulin sensitivity

Question 51

What is the approximate % total energy output for physical activity?

Answer 51

25% (Highly variable among individuals)

Question 52

What other things can diet influence & how?

Answer 52

Disease risk through chromatin modifications

Question 53

What are 3 methods to assess body mass and fat?

Answer 53

BMI, skin-fold thickness, underwater weight

Question 54

What contributes to Lean Body Mass?

Answer 54

Body muscle

Question 55

What contributes to Fat-Free Mass?

Answer 55

Lean body mass + water & minerals

Question 56

What contributes to Body Weight?

Answer 56

Fat-free mass + fat mass

Question 57

Define the ideal body weight

Answer 57

The weight range that maximizes health (minimizes risk of diseases that affect lifespan & quality of life)

Question 58

At which BMI range does the least risk for mortality occur?

Answer 58

18.5 - 24.9

Question 59

What are some reasons that obesity has increased in the past few decades?

Answer 59

Increased availability of high energy foods, decreased physical activity. Both in combination with genetic predisposition.

Question 60

What is the statistic for how many Canadians are overweight?

Answer 60

~1:3

Question 61

What is the statistic for how many Canadians aren't getting enough exercise?

Answer 61

~8:10

Question 62

What is the statistic for how many people maintain weight loss over a 5 year period?

Answer 62

~1:20

Question 63

What BMI has weight-associated health risks, especially in males?

Answer 63

>25

Question 64

What BMI is considered obese?

Answer 64

>30

Question 65

What body fat % indicates obesity in each gender?

Answer 65

25% for men, 35% for women

Question 66

What measure is a good indicator of obesity & co-morbidites?

Answer 66

Waist to Hip Ratio

Question 67

Define metabolic syndrome

Answer 67

The condition in which a person has a combination of 3+ metabolic problems (often associated w/ obesity)

Question 68

What are the 3 conditions included in metabolic syndrome?

Answer 68

Atherogenic dyslipidemia (ex. high serum cholesterol), hypertension, abnormally high serum glucose

Question 69

What waist circumference indicates obesity in each gender?

Answer 69

>100cm male, >90cm female

Question 70

What are the 2 types of fat?

Answer 70

Essential fat, & fat storage