Biology of Obesity- Fundamentals of Energy Balance

Question 1

name the laws of thermodynamics (5)

Answer 1

1. 1. energy can neither be created or destroyed
2. the food we eat is potential energy
3. potential energy is energy stored in a physical system with potential to be converted into work
4. changes in stored energy= changes in adiposity
5. “The Physics of Weight Change”

Question 2

in what ways is energy measured (4)

Answer 2

1. Joule- standard unit for potential energy (not used in north america)
2. Calorie- amount of energy required raise temp of 1kg of water by 1 degree cel. (equal to 4184 Joules.
3. calorie- amount of energy required to raise temp of 1g of water by 1 degree cel. (equal 4.184 Joules
4. kcal- used to express food energy’ represents a Calorie

Question 3

how much bigger is Calorie (Big) than a calorie (small)

Answer 3

1000x larger

Question 4

define energy balance

Answer 4

result of equalibrium between energy intake (EI) and energy expenditure (EE)

Question 5

Talking about energy balance, what must happen to result in weight gain/obesity

Answer 5

energy intake (EI) > engery expenditure (EE).
EI must exceed amount of EE

Question 6

during adulthood maintenence of body weight depend on what overtime?

Answer 6

depends on the energy derived from food/drink being equal to EE.

Question 7

what percent of deviation frm energy balance can result in weight changes?

Answer 7

1-2% of daily EI over long term

Question 8

Components of EI & EE

Answer 8

EI: food (carbohydrates, lipids, protien) & alcohol
EE: Basal Metabolism/resting metabolism, Thermogenesis, Non-exercise activity thermogenisis & Physical Activity

Question 9

name the macro nutrients & the kcal amount per 1g of macronutrient.

Answer 9

fat (1g=9kcal)
protien (1g=4kcal)
carbohydrate (1g=4kcal)
alcohol (1g=7kcal)

Question 10

define basal metabolic rate/resting metabolic rate

Answer 10

required energy to sustain vital body functions

Question 11

difference between BMR & RMR

Answer 11

used interchangeably. RMR is measured under extreme conditions (no talking, no moving)

Question 12

define thermic effect of feeding (TEF)

Answer 12

response to digestion of food and uptake.

Question 13

what carbohydrate has the highest thermic effect of feeding?

Answer 13

protien has the highest, fats have the lowest

Question 14

define exercise activity (EA)

Answer 14

energy used for purposeful movement

Question 15

define non-exercise activity thermogenisis (NEAT)

Answer 15

spontaneous physical activity (fidgeting) that is not planned

Question 16

why is the cost to move/maintain a larger body higher?

Answer 16

higher RMR due to respiring mass. More energy is needed just for the body’s internal features to function.

Question 17

what is a flaw with benedict’s prediction for calculating RMR

Answer 17

there is an increase of error with bigger body sizes.

Question 18

how many kcals (or Calories) is 1lbs of body weight

Answer 18

3500 kcal/Calorie

Question 19

What is the physics of weight balance (Wishnofsky’s rule)

Answer 19

consume an extra 3500kcal=gain 1lbs
burn 3500kcal= loose 1lbs

Question 20

What is the flaw with the physics of weight balance? (Wishnofsky’s rule)

Answer 20

-does not account for plateaus
-was done in a strict and tightly controlled clinical setting (not realistic)
-does not take into account body size or comp.

Question 21

number of kcals required for 1lbs of body weight loss changes depending on what (4)

Answer 21

-how long the dieting period lasts
-what type of diet is eaten
-level of physical activity
-age & biological sex

Question 22

what does the energy content of weight loss depend on?

Answer 22

will depend on the composition of the weight loss and how the body adapts to the energy restriction placed on it.

Question 23

what are the different composistions of weight loss (4) & what order are they lost in.

Answer 23

In order from first to last:
1. water
2. glycogen
3. protein
4. fat

Question 24

define static energy balance

Answer 24

assumes a change in one side of the energy balance equation doesn’t change the other side of the equation. And that changing one side more than the other results in an imbalance.

Question 25

what is a flaw in static energy balance

Answer 25

-one change of the scale will change the other side.
-It reaches equilibrium

Question 26

what are the components of static energy balance

Answer 26

EI & EE

Question 27

define dynamic energy balance

Answer 27

Recognizes energy balance is dynamic, especially during periods of weight change.
A change in one side (EI) does change the other side (EE)

Question 28

How does EE change when EI is changed? Explain using dynamic energy theroy

Answer 28

As EI increases the bodys RMR increases, ultimately increasing EE due to RMR increase.

With weight loss as EI decreases so does EE because it takes less energy to keep the body running for a smaller body.

Question 29

actual amount of weight gained depends on what ?(5)

Answer 29

-extra kcals consumed
-composition of the diet
-body comp
-type of exercise
-level of physical activity

Question 30

what 2 models are used to predict weight change/loss

Answer 30

1. pennington model
2. NIH model

Question 31

what is the carbohydrate insulin model (CIM) & what it suggests/implies (2)

Answer 31

a theory that explains how high carb diets can lead to weight gain

-suggest that body stores excess calories as fat
-implies that not all calories are equal

Question 32

what is the newer energy balance model (EBM) and its flaw (1)

Answer 32

proposes that the brain controls intake to regulate body weight through complex endocrine, metabolic & nervous system signals.

flaw: assumes all calories are equal (metabolicilly).