This ppt contains all the details about what is obesity, etiology, & mainly focuses on various methods of assessment of obesity from field tests to lab tests.
3.
Overweight & obesity terms are used interchangeably
but has different meaning.
Overweight is defined as body weight that exceeds
the normal or standard weight for a particular person
based on height & frame size.
An overweight person might have lower than normal
body fat content.
Obesity refers to the condition of having excessive
amount of body fat. (men with >20% & female with
>35% of body fat)
INTRODUCTION
4.
Intake & output
The total amount of energy expended each day is
sum of 3 components –
Resting metabolic rate (60 – 75%)
Thermic effect of a meal (10%)
Thermic effect of activity (15 – 30%)
All 3 components increase with overeating
CONTROL OF BODY WEIGHT
5.
In physical fitness, body composition is used to
describe the percentages of fat, bone, water and
muscle in human bodies. Because muscular tissue
takes up less space in our body than fat tissue,
our body composition, as well as our weight,
determines leanness.
Muscle mass includes the weight of the muscles in
your body in kilograms or pounds. While the body
fat percentage measures the amount of fat your body
holds.
Body composition
6.
COM PONENTS MALE FEMALE
MUSCLE 45% 36%
ESSENTIAL FAT 3% 12%
NON ESSENTIAL FAT 12% 15%
BONE 15% 12%
OTHER 25% 25%
10.
Apples- Android
Upper-body obesity
Associated with more heart disease, HTN, Type II
Diabetes
Abdominal fat is released right into the liver
Encouraged by testosterone and excessive alcohol
intake
Defined as waist measurement of > 40” for men and
>35” for women.
It is clinically more important as disease are more
correlated with this abdominal fat.
11.
Pears – Gynecoid
It is characterized by accumulation of fat around hip
and buttocks.
Lower-body obesity--Pear shape
Encouraged by estrogen and progesterone.
Less health risk than upper-body obesity.
After menopause, upper-body obesity appears.
17.
Hydrostatic weighing
Also known as underwater weighing, hydrostatic
body composition analysis or hydrodensitometry.
Valid, reliable & widely used laboratory method
Works on archimede’s principle.
Assess total body density(Db) – function of
respective amount of muscles, bone, water & fat in
the body.
Measures total body volume (BV)
Db = Body weight / BV
19.
Duel energy X-ray absorptiometry – measures bone
mineral density.
DXA scans can also be used to measure total body
composition and fat content with a high degree of
accuracy comparable to hydrostatic weighing.
However, it has been suggested that, while very
accurately measuring minerals and lean soft tissue (LST),
DEXA may provide skewed results due to its method of
indirectly calculating fat mass by subtracting it from the
LBM and/or body cell mass (BCM) that DXA actually
measures.
DXA scans are also used to assess adiposity in children,
especially to conduct clinical research.
DEXA
21.
scientifically validated densitometric method to measure
human body composition.
ADP is based on the same principles as the gold standard
method of hydrostatic weighing, but through a
densitometric technique that uses air displacement rather
than water immersion.
Air-displacement plethysmography offers several
advantages over established reference methods, including
a quick, comfortable, automated, noninvasive, and safe
measurement process, and accommodates various subject
types (e.g., children, obese, elderly, and disabled persons).
Air displacement plethysmography
23.
Radio frequency current is introduced in body
through electrodes.
Fat has less number of electrolytes.
Water is less conductive.
Bioelectrical impedance
24.
They can differentiate subcutaneous from visceral fat
and so are important in research purposes.
CT / MRI
26.
Refers to measurement of the size & proportion of
human body.
Uses circumference, skeletal breadths, skinfold
thickness & segment lengths.
These methods are relatively simple, inexpensive &
do not require high degree of technical skills &
training.
27.
Waist circumference (WC) is an indicator of health
risk associated with excess fat around the waist.
Start at the top of your hip bone, then bring the
tape measure all the way around your body, level
with your belly button. Make sure it's not too tight
and that it's straight, even at the back. Don't hold
your breath while measuring. Check the number on
the tape measure right after you exhale.
Waist circumference
HIGH RISK
MEN - >102cm (>40in)
WOMEN - >88cm (>35in)
28.
A high waist circumference is associated with an increased
risk for type 2 diabetes, dyslipidemia, hypertension, and
CVD in patients with a BMI in a range between 25 and 34.9
kg/m2.
Monitoring changes in waist circumference over time may be
helpful, in addition to measuring BMI, since it can provide an
estimate of increased abdominal fat even in the absence of a
change in BMI.
Furthermore, in obese patients with metabolic complications,
changes in waist circumference are useful predictors of
changes in CVD risk factors.
In some populations, waist circumference is a better indicator
of relative disease risk than is BMI.
Waist circumference also assumes greater value for
estimating risk for obesity-related disease at older ages.
29.
Calculated as Weight(kg)/Height(m^2)
BMI measures individual’s total weight relative to its
height.
BMI may be high in a vey muscular person.
For similar BMIs women have greater fat mass than
their male counterparts.
So BMI may be misleading in certain cases.
BMI
30.
CATEGORY WHO criteria for
BMI
ASIAN criteria
for BMI
DISEASE RISK
UNERWEIGHT < 18.5 < 18.5 -
NORMAL 18.5 – 24.99 18.5 – 22.9 -
OVERWEIGHT 25 – 29.99 23.0 – 24.9 Increased
OBESE I 30 – 34.99 25.0 – 29.9 High
OBESE II 35 – 39.99 30.0 – 34.9 Very High
OBESE III (MORBID
OBESITY)
> 40 > 35 Extremely high
31.
It is the dimensionless ratio of the circumference of
the waist to that of the hips.
It determines how much fat is stored on your waist,
hips, and buttocks.
Waist : Hip
Health risk Female Male
Low <0.80 < 0.95
Moderate 0.81 – 0.85 0.96 – 1.0
High >0.85 > 1.0
32.
Measurement procedure:
Stand up straight and breathe out. Use a tape measure
to check the distance around the smallest part of your
waist, just above your belly button. This is your waist
circumference.
Then measure the distance around the largest part of
your hips — the widest part of your buttocks. This is
your hip circumference.
Calculate your WHR by dividing your waist
circumference by your hip circumference.
33.
our waist-to-height ratio provides information on
whether your weight is appropriate for your height
and whether or not you're at increased risk for
chronic diseases like heart disease.
It specifically reflects your distribution of body fat.
Many health professionals find your waist-to-height
ratio more accurate than BMI (Body Mass Index).
Determining your waist-to-height ratio is fairly
simple. Once you determine your ratio, you can get a
good idea of whether or not you're at a healthy
weight.
Waist : Height
34.
According to Ashwell’s Shape Chart,
A WHtR between .40 and .50, which typically creates a
pear-shaped body, is ideal, but a person should
consider shedding some weight when his or her
WHtR ratio is between .50 and .60 (somewhere
between a pear and an apple).
At a ratio of .60 and above, which typically produces
an apple-shaped body.
36.
Indirectly measures the thickness of subcutaneous adipose
tissue.
To use SKF method to calculate total body density, in
order to calculate relative body fat (BF%), certain basic
relationships are assumed –
SKF is a good measure of subcutaneous fat.
The distribution of fat subcutaneously & internally is same
for all individuals within each gender.
Due to relation of subcutaneous fat & total body fat, sum of
several skinfolds can be used to estimate total body fat.
Age is an independent predictor of Db for both men &
women
Skin fold measurement
37.
Take all SKF measurements on right side of body.
Carefully identify, measure & mark the SKF site.
Grasp the SKF firmly between the thumb & index finger of left
hand, keeping it 8cms apart on a line perpendicular to long
axis of SKF, lift the fold 1cm above the site.
Keep the fold elevated while taking measurements.
Place the jaw of the caliper perpendicular to the skin fold, 1cm
below thumb & index finger, release the jaw pressure slowly.
Take SKF measurement 4sec after jaw pressure is released.
Open the jaws of caliper to remove from the site.
Standardized procedure for measurement
38.
Identify & mark the site properly.
Read the dial of caliper to the
nearest 0.1mm (harpenden or
holtain), 0.5mm (large), 1mm
(plastic calipers).
Minimum 2 measurements at each
site.
Prefer rotational order of sites
Skin should be dry & lotion free
Do not measure immediately after
exercise
Recommendations
40.
The Jackson and Pollock equation to calculate body
density –
In women (triceps, suprailiac, thigh) –
1.0994921 - (0.0009929 x Σ SKF) + (0.0000023 x Σ
SKFsquare) - (0.0001392 x age).
For men (chest, abdomen, thigh) –
1.10938 - (0.0008267 x Σ SKF) + (0.0000016 x Σ SKF
squared) - (0.0002574 x age).
Once you've calculated body density, you calculate
percent fat by using the equation –
[(495 / body density) - 450] x 100.
Calculations
41.
Total of all four sites is considered -
15-45 mm – 8-22 % of total body fat
46-75 mm – 23-30 % of total body fat
76-150 mm – 31-40 % of total body fat
151-170 mm – 41-45 % of total body fat
Up to 22% it is normal (males)
Up to 30% it is normal (females)
44.
It is a chronic medical condition
Definition of successful treatment:
Attainment of normal weight
No treatment induced morbidity
This is rarely achieved in clinical practice.