Dear Colleagues
This topic is targeting the understanding of the methods of body composition and their application in clinical practice. Since Obesity is a major cause of morbidity worldwide, this has to be under a healthcare program and to be recognized by the healthcare system and the providers.
Best regards
Dr Majid Abi Saab
2. Bo dy Co m po sitio n
Most methods consider body having two components:
• fat component, i.e. fat mass
• fat-free component, i.e. fat-free mass (FFM)
Body fat %
• average values: women, ~25%; men ~15%
• minimal values: women, 8-12%; men – 5%
• considered obese: women, >30%; men >20%
e sse ntialand no n-e sse ntialfat
5. Rating s o f % Fat (ag e s 20 -29 yr)
Rating Men Women
Excellent 6-9 10-17
Good 10-14 17-21
Acceptable 15-19 21-25
Too Fat 20-22 27-32
Obese >22 >32
6. De te rm ining Ide alBo dy We ig ht
Indire ct appro ache s
Me tro po litan he ig ht– we ig ht table s
body mass index (BMI)
• weight (kg) / height2
(m2
)
• ideal range is 18-25
• >30 considered obese
Dire ct appro ache s
• hydrostatic (underwater) weighing
• anthropometric (skin-fold) measurements
• bioelectrical impedance analysis (BIA)
• air-displacement plethysmography (BOD POD volume)
• DEXA The Most Accurate
9. GE Lunar DEXA Body composition
FDAapprovedtheLUNARDEXAforBodyComposition
Indications foruse: The GE LunarBody Composition
“…management of diseases/conditions where the disease/condition itself, or it's
treatment, can affect the relative amounts of patient fat and lean tissue. “
Main indications: Obesity | Metabolic Syndrome | Chronic Steroids treatment | Back
pain related android obesity.
“Some of other diseases/conditions for which body composition values are useful
include chronic renal failure, anorexia nervosa, AIDS/HIV and cystic fibrosis.
10. X-ray Source
X ray Absorption
Bone has a Higher
XRay Attenuation than
Soft Tissue
11. DEXA Physics
Xray attenuation is depending on the amount, type of tissue and energy level
Bone
Soft Tissue
Low Energy High Energy keV
Abs(HE keV) = Abs(HE keV) ST + Abs(HE keV) B
Abs(LE keV) = Abs(LE keV) sT + Abs(LE keV) B
Abs(HE keV) = Abs(HE keV) ST + Abs(HE keV) B
I(HE keV) = Io exp(µHE.ST DST + µHE.B DB)
Abs(LE keV) = Abs(LE keV) ST + Abs(LE keV) B
I(38keV) = Io exp(µLE.ST DST + µLE.B DB)
Ab
s
DST ; DB could be calculated
and so MB =DB x AreaB
MST = DST x AreaST
12. Measure Bone/Fat/Lean Using DXA
-3Compartment model
Define anatomical region
Define bone area (green pixel)
Calculate Bone mass using two energies
Outside of bone region, R-value -> %Fat using two
energies
Use local uniform composition over Bone region to
calculate total soft tissue and after fat - lean in each
sub-regions
Calculate Total weight by summing up Fat, Lean
and Bone masses for all sub-regions
13. Obesity
Female (42years) (Height: 162 cm / Tissue (kg) (Fat + Lean): 96,2 to
93kg)
A/G decrease : DECREASE fat in android!
Fat (kg): 49,9 to 44,6 to 45,7 / Lean (kg): 46,2 to 47,4 to 47,3kg
14. Normal Weight Obese Syndrome
Female (26 years) (Height: 158 cm / Total Mass (kg) : 54,8 to 52,3kg)
Follow up case over1,5 year
BMI from22,2 to 21,2 (normal)
15. Normal Weight Obese Syndrome
Female (26 / H:158 cm / W:54,8 to 52,3kg) Tissue (kg) (FM + LM): 52,7kg to 50,2kg
What did she lose over1,5 year, Fat and/orLean?
Fat (kg): 18,9 to 16,5 / Lean (kg): 33,7kg to 33,7kg
16.
17.
18. Ask yourself
• Are you Obese?
• Do you suffer from Obesity related disorders?
• Metabolic?
• Chronic Back Pain, Knee/Hip OA?
• Do you have difficulties on making regular/sport activities?
• Is your HAQ within normal?
19. We ig ht Manag e m e nt
• diet modification
• physical activity modification
• behavior modification
Principles Common to Successful Programs
20. Weight Management
base d o n Ene rg y Expe nditure (kcal/m in)
Activity 56 kg 83 kg
basketball 7.3 11.5
Circuit training 9.8 15.4
Cycling (9.4 mph) 5.6 8.3
Running (9 min/mile) 10.8 16.0
Running (7 min/mile) 13.3 18.5
Swimming (slow) 7.2 10.6
Swimming (fast) 8.7 12.9
Tennis (singles) 6.1 9.0
Walking (3.0 mph) 4.5 6.6
Sitting (quietly) 1.2 1.7
21. We ig ht Manag e m e nt
base d o n Intake
Weight change = Calories (energy) intake – energy
expenditure
Ene rg y Intake
caloric density
• CHO = 4 kcal/g
• protein = 4 kcal/g
• fat = 9 kcal/g
• ethanol = 7 kcal/g
influence of diet composition
22. Effe cts o f lo w-
e ne rg y intake o n
RMR
Bray, Lancet, 1969
23. Yo ur are o ffe re d a tiny part o f Snicke r’s candy
bar.
It co ntains 6 g o f fat and the re is 1 0 0 kcalo f
e ne rg y.
What is the pe rce ntag e o f e ne rg y that co m e s
fro m fat?
a. 6 kcal
b. 600 kcal
c. 6%
d. 54%
e. 60%
f. cannot be determined
24. Weight Management
Calculate % Intake fro m Fat
Breakfast - McDonald's
Total Energy
(kcal)
Fat
(g)
Sausage McMuffin w/Egg 517 33
1% Milk - 8 oz 110 2
Hash Brown Potatoes 125 7
Lunch - Burger King
Bacon Double Cheeseburger 510 31
French Fries - regular 227 13
Chocolate Shake - 10 oz 374 11
Snack
Snicker's Candy Bar 280 13
Dinner - Taco Bell
Two Tacos 372 16
Combination Burrito 404 16
Pepsi - 24 oz 288 0
TOTAL (40% of intake from fat) 3,207 142
25. Weight Management
Be havio r Mo dificatio n
• avoid automatic eating
• plan meals ahead of time
• don’t serve self more food than should eat
• avoid social binges
• practice other stress management techniques
• set realistic goals
• incorporate physical activity into program