Tool 2 - Obesity prevalence ready-reckoner

This tool can be used to estimate the number of adults (aged 16 and above) or the number of children aged 4-10 years within a primary care trust who are obese or overweight.

NB: Please note that the ready-reckoner uses national data and does not take into account local factors such as ethnicity, deprivation or other factors that might affect overweight and obesity prevalence.

(A modified version of the ready-reckoner can be used to estimate the number of overweight people – those with a BMI more than 25.0kg/m2 – using the data on prevalence of overweight in different age groups from the Health Survey for England 2004.)

Go to online ready-reckoner for adults.
Go to online ready-reckoner for children.

How to use the ready-reckoner

The ready-reckoner can be used to estimate:

  • the number of people who are obese – measured by Body Mass Index (BMI) of more than 30.0kg/m2
  • the number of people with central obesity as measured by a raised waist circumference. A raised waist circumference has been taken to be 102cm (40 inches) or more in men and 88cm (35 inches) or more in women. These levels have been used to identify people at risk of the metabolic syndrome, a disorder characterised by increased risk of developing diabetes and cardiovascular disease. Central obesity, as measured by waist circumference, is reported to be more highly correlated with metabolic risk factors (high levels of triglycerides and low HDL-cholesterol) than is elevated BMI.

Follow the simple steps below:

  • In cells A1 to A7 and B1 to B7, enter the actual numbers of residents in each age group, based on latest population estimates for your area.
  • Calculate the other cell values according to the formulae.

Example  – Southwark Primary Care Trust: Adults aged 16 and over

The following is an example of how to use the ready-reckoner, based on 2001 census figures for Southwark Primary Care Trust, London.

Thus, the total estimated number of adults (aged 16 years and above) who are obese in Southwark PCT is 41,718, and the total number who have a greater health risk due to a raised waist circumference is 64,150.

TOOL: OBESITY READY-RECKONER Adults aged 16 and over

Use this online calculator to estimate local prevalence. Simply fill the cell values as per the instructions above.

Tool: Obesity ready-reckoner - Adults aged 16 and over
    PCT population   Estimate of number of people who are obese Estimate of number of people who have a raised waist circumference
    (Enter actual numbers)   (BMI greater than 30kg/m2)                      (Male 102cm or above. Female 88cm or above)
  Age
Male (A)
Female (B)
Male (C)
Female (D)
Male (E)
Female (F)
1 16-24    
2 25-34    
3 35-44    
4 45-54    
5 55-64    
6 65-74    
7 75 plus    
8 SUB-TOTAL    
9 TOTAL
 
 
Source: The formulae for obesity are based on the Health Survey for England 2004. The formulae for waist circumference are based on the Health Survey for England 2003.

To print your calculations

If you would like to print your calculations, simply click on 'File', then 'Print' within your internet browser.

If you have any queries please contact: Faculty of Public Health