Body Mass Index

The Body Mass Index (BMI) is a method used by healthcare professionals; it uses a person’s weight and height in order to calculate whether the person is healthy, overweight or obese. This method has been used for years and it has been suggested that there is a strong link between a high BMI, disease and death. However, this theory has been challenged and is currently a debatable topic.


Central obesity refers to the amount of fat specifically around your middle. Certain studies have concluded that a better indicator of health is to measure a person’s central obesity rather than BMI.  These studies have concluded that people with central obesity have a worse long-term survival rate than people who are classed as overweight or obese according to their BMI alone. The logic surrounding this argument is that central obesity indicates that an individual’s fat is primarily surrounding their middle where vital organs are located. BMI only uses weight and cannot determine where this fat is located, or whether the weight is fat or muscle. Consider a body builder; their BMI would indicate that they are overweight or obese.

With this topic remaining controversial, a recent study carried out at Loughborough University in the UK investigated the association between central obesity, BMI and risk of disease and death in a population of approximately 42,000 people. Participants were chosen for the study from 10 survey years of Health Surveys from England and Scotland.

BMI results are categorized as:

  • Normal weight = 18.50 to 24.99 kg/m2
  • Overweight = 25.00 to 29.99 kg/m2
  • Obese= 30.00 kg/m2

Central obesity is calculated using the measurements of the waist and hips. The World Health Organization classifies central obesity as having a waist-to-hip ratio of 0.85 or higher in women; and a waist-to-hip ratio 0.90 or higher in men.

The aim of this study was to obtain results that support the argument that people with central obesity with a normal BMI have the worst long-term survival. The results were limited but clearly showed that participants with central obesity were at an increased risk of death.

Despite these findings, this topic of BMI vs central obesity will remain controversial until further research and data are obtained. What cannot be disputed is that being overweight, whether it is fat around your middle, hips or thighs is still considered to increase your overall risk of ill-health and premature death. This leaves us with the conclusion that it is best to keep your BMI within a reasonable range and your central body fat to a minimum. This is achieved, as we already know, through a balanced diet and regular exercise.


Written By: Jade Marie Evans, MPharm, Medical Writer

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