At SEQS, a number of methods are used to determine whether you are obese and have associated metabolic complications. These include:

• Body Mass Index (BMI)
• Bioelectrical Impedence
• Waist circumference
• Other tests

## THE BODY MASS INDEX (BMI)

One of the measures used to estimate body shape is the Body Mass Index (BMI). The BMI compares weight and height to determine if a person is over- or underweight for their height. To calculate and categorise your BMI:

1. Click on the following link:

The BMI Calculator

Link source: Dept of Health and Ageing, Australian Government

1. Find out which range you are in by comparing your BMI with the following WHO table:
 Who Classification of Obesity* BMI kg/m2 Normal 18.5-24.99 Overweight ≥ 25 Preobese 25-29.99 Obese ≥ 30 Obese class I 30-34.99 Obese class II 35-39.99 Obese class III ≥ 40 Super obese 50.59.99 Super Super obese ≥ 60

Source: World Health Organisation (2013).

*Cut-off ranges may be different for different ethnic groups

If your BMI is >35 kg/m2, you are likely to have significant health problems; however this is not always true and to certain extent depends on your age, build and ethnic background:

• BMI is not able to differentiate between muscle and fat mass, so people who are very muscular will have a high BMI
• Polynesians will have a larger muscle mass, weighing in heavier, so they may be very healthy but have no risks
• Asians generally have low fat mass, so the BMI for morbid obesity in an Asian is 27.5.

## BODY COMPOSITION ANALYSIS

One important investigation that we do is full body composition analysis.This is done using a bioelectrical impedence machine, which passes a harmless electrical signal through the body, to determine its composition.

This analysis is able to provide information on

• BMI
• % fat of total body weight
• % lean body mass
• % body water content
• degree of obesity
• an estimate of ideal weight.

## WAIST CIRCUMFERENCE

Fat distributed predominantly around the waist is also a risk factor for health complications such as cardiovascular disease and type II diabetes. Fat predominantly deposited around the hips and buttocks doesn’t have this same risk.

Measure your waist circumference using a tape measure and check it against the table below. Overwight and obese Caucasians are at higher risk of metabolic complications relative to the general population if their waist circumference is:

 Risk of metabolic complications Waist Circumference (cm) Men Women Increased ≥ 94 ≥ 80 Substantially increased ≥ 102 ≥ 98

## PERCENTAGE OF EXCESS BMI LOST (%EBMIL)

The percentage of excess BMI lost is currently the best method to compare the treatments for moderate and severe obesity. %EBMIL uses BMI 25 as the upper limit of normal. It is calculated from the formula:

% EBMIL = Pre-operative BMI  -  Current BMI            x     100

Pre-operative BMI – 25

## OTHER TESTS

A number of blood tests are performed to see if there are any other causes for obesity present e.g. under-active thyroid gland or an undiagnosed condition.

Insulin resistance is commonly found. This appears to be the first step to diabetes.