Body Composition & Obesity Flashcards
1
Q
What is BMI?
A
The most common measure of obesity
weight (kg)/ height (m^2)
2
Q
Limitations of BMI?
A
- Cannot distinguish different body composition
- not suitable for pregnancy
- shows that athletes who have high muscle mass have a high BMI however they have low body and no disease risks
3
Q
BMI Table
A
<18.5= underweight
18.5-25= healthy
25-30= overweight
>30= obesity
4
Q
2 compartment model
A
fat and fat-free mass (anything that is not fat like bone, muscles etc)
5
Q
3 compartment model
A
fat-free mass, bone mass and lean mass (fat and bone free)
6
Q
4 compartment model
A
better imaging
7
Q
8 techniques of assessing body fat
A
- Densitometry
- Skinfold measurements
- Computed tomography (CT scan)
- Magnetic resonance imaging (MRI)
- Total body density (DXA)
- Age, height and weight tables and weight prediction equations
- Cadaver analysis
- Bioelectric impedance analysis (BIA)
8
Q
Cadaver analysis
A
- takes direct measure of body tissue
- most accurate but impractical method
- used to validate the accuracy of other devices
- the majority of the data was taken from white males meaning there are limitations when seeing results for other ethnicities
9
Q
Densitometry
A
- density is proportional to fat-free mass (higher desity= higher FFM)
- volume of water/ air displaced= volume of the object
10
Q
Different methods of densitometry
A
- air displacement
- plethysmography (bod pod)
- hydro densitometry (underwater weighing)
11
Q
Bioelectrical impedance analysis
A
- fat and lean tissue have different conductance (fat tissue= insulator; no water, lean tissue- conductor; contains water)
- measures the impedance of electrical current (slower= more fat)
- equations to predict body fat
- can be affected by hydration status
12
Q
Skinfold measures
A
- takes mm measures of skin and fat thickness at various body sites
- subcutaneous
- sites: biceps, triceps, subscapular and supra-iliac, thigh, calf, abdomen
13
Q
Computed tomography
A
- 4C model
- consists of radiation hence not recommended
- expensive and time-consuming
- high-density tissues show up whiter (bone) and low-density tissues show up darker grey (fat)
14
Q
Magnetic resonance imaging
A
- 4C model
- magnet fields instead of radiation (preferred for research)
- expensive and time-consuming
- fat is lighter and bone is darker grey
15
Q
Dual-energy X-ray absorptiometry
A
- 3C model
- low dose of radiation
- less costly
