Weight management

Question 1

What is energy balance?

Answer 1

positive energy balance = weight gain

negative energy balance = weight loss

Question 2

What is the average weight gain of americans?

Answer 2

0.45-0.9kg/year over past decade

Question 3

How many calories is a kg of weight gain?

Answer 3

7,700calories with excess energy stored at about 50% efficiency
decreasing energy intake by 100cal/day would stop this weight gain

Question 4

How do we measure the body?

Answer 4

body size - volume, mass, length, surface area

body structure - arrangement of body parts

Question 5

Why do we not want fat on an athlete?

Answer 5

in any spor where the body must be moved this is detrimental to performance.
adds body mass without capacity to generate force
increases the mass that must be moved
increases the amount of metabolically active tissue

Question 6

What are the usual percentage body fats?

Answer 6

olympic marathon runners - 3-4%
tour de france cyclists - 4-6%
rugby - 12-15%

Question 7

What are the usual body masses for female athletes?

Answer 7

female distance runners - 50-55kg
female shot putters - 75-85kg
ballet - 45kg

Question 8

How do you calculate BMI?

Answer 8

body mass/height2

Question 9

what are the BMI ranges?

Answer 9

underweight - 18 and under
normal 18.5-25
overweight - >25
obese - >30

Question 10

What are the limitations of BMI?

Answer 10

Does not take into account body composition
Results in misclassification of some athletes and individuals
two individuals may have the same BMI but not same composition
Not good for children or elderly
Overall good for population assessment

Question 11

What is hydrostatic weighing?

Answer 11

different tissues have different densities
based on the principal that fat is less dense than lean mass. It is considered the gold standard for measuring. has an error of 2-5%. problems include failure to exhale and GI gas etc

Question 12

What is the skinfold measurement?

Answer 12

based on the principal that a relatively constant portion of fat is under the skin
relatively good method
error 5%
inexpensive
should be done by the same person

Question 13

What is the air diaplacement measurement?

Answer 13

displaces air based on body volume
body density can then be calculated by mass/volume
slight lower values than under water weighing
good reliability

Question 14

What is bioelectric impedance?

Answer 14

based on the principal that lean tissue conducts electricity better than fat
less resistance = higher water content
need to control hydration, position of electrodes, previous exercise

Question 15

How is imaging used to measure body mass?

Answer 15

DEXA/NMR
take images of body sections and calculate fat
very accurate 2-3% error
used to be prohibitively expensive but price is coming down

Question 16

What is essential fat?

Answer 16

fat present in nerve tissue, bone marrow, organs and all membranes
cannot lose this fat without physiological consequences
3% of body mass in men. 12% of body mass in women

Question 17

What is non essential fat?

Answer 17

storage of excess energy

Question 18

What is the total body fat for men?

Answer 18

12-15%

<5% not recommended

Question 19

What is the total body fat for woman?

Answer 19

25-28%

<12% not recommended

Question 20

What is the weight loss registry?

Answer 20

a database of those who have maintained a weight loss of over 15kg for over a year

Question 21

What is weight loss positively associated with?

Answer 21

decreased refined sugars and fat, snacks and sweets

increased intake of total CHO and fibre, low fat dairy foods, breads, cereals, fruits and veges

Question 22

What should the diet composition of someone who is trying to lose weight be?

Answer 22

more CHO than Fat as CHO stores are limited but fat stores are not

Question 23

Why can a decreased fat diet be effective?

Answer 23

because fat is energy dense and has 2x as much energy per gram than CHO/protein
high fat foods taste good and increase spontaneous intake of food
fat is efficiently stored and takes very little energy to do so
fat intake does not increase it’s oxidation

Question 24

What weight loss method should the clinically obese use?

Answer 24

very low energy diet.
liquid supplements
done in a hospital setting
not conducive to activity
nausea, bad breath, hunger, light headedness, hypotension

Question 25

What are food-combination diets?

Answer 25

certain foods cannot be combined

end up being calorically restricting and does not matter what combinations are

Question 26

What is a high protein diet?

Answer 26

Thermic effect of protein and satiety.

Thermic effect calculates to minimal losses even over a year

Question 27

What is a zone diet?

Answer 27

40-30-40
based on selective scientific evidence
hard to follow being calorically restricting
detrimental to exercise performance

Question 28

What is the low CHO diet?

Answer 28

atkins
ketogenic diet to increase fat metabolism and appetite suppression
eliminates healthy fruit/fibre
depletes glycogen
nasty byproducts
promotes high fat intake
body starts to crave CHO

Question 29

What has lead to the body weight set point?

Answer 29

decreased mass decreases RMR.

so smaller you get less weight you lose. bigger you get more weight. so weight does not vary that much

Question 30

What is android obesity?

Answer 30

metabolically more active, fat stored in abdo

Question 31

What is gynoid obesity?

Answer 31

fat stored in lower body, harder to metabolise

Question 32

Why is weight training as effective as cardio?

Answer 32

increases lean mass and RMR

good for body composition