Are People in their 20s Being Misclassified as Obese?

Research from the University of Wolverhampton has shown that Body Mass Index (BMI) thresholds need to be redefined to stop people being misclassified as oProfessor Alan Nevill research into BMI Misclassification of obesity.verweight or obese.

Professor Alan Nevill from the University of Wolverhampton has found that people in their 20s whose BMI is between 30 and 33 (males) and between 30 and 32 (for females) are being misclassified as obese.

Using a previously published dataset taken from the Allied Dunbar National Fitness Survey (ADNFS) of 4316 subjects aged 16 or over, research has been undertaken into the association between the measurements of body fat and Body Mass Index (BMI). Two leading professors in the field of health and wellbeing at the University of Wolverhampton have discovered that some young overweight people whose BMI is greater than 30 should not be classified as obese.

Across the board, medical and health professionals are using the same BMI overweight and obese thresholds to assess body fat percent regardless of their age or gender without taking into consideration any other factors which could affect this BMI ratio – such as muscle mass.

‌Professor Alan Nevill said:  “Following years of study carried out by myself and my colleague, George Metsios, we have identified that you can’t assume the classification of 30 BMI Index to be the gold standard of obesity measurement and it is certainly not a true cut off point for everyone regardless of their age or gender.

“This anomaly is most certainly resulting in some young people being classified as obese when they actually are not, and some older people being classified as not obese when they actually are.

“To conclude, we must start to redefine overweight and obese levels of BMI thresholds for different gender and age groups. Health practitioners need to adopt new practice and consider an alternative strategy in prescribing BMI thresholds.  Our findings suggest that younger people should have higher BMI cut-off points, probably due to them having a higher percentage of muscle mass than older subjects, but conversely the threshold for older people should be reduced to a more conservative level.”

The statistical measurement which classifies obesity in adults is that anyone above 30 is classified as obese and below 30 (but greater than 25) they would be classified as overweight. The BMI ratio is used by doctors to work out if someone is overweight or obese and so at risk of problems from high blood pressure to heart disease.  It is traditionally calculated by dividing a person's weight in kilograms by their height in metres squared with the aim of giving a measure of an individual's body fat. A BMI of between 18.5 and 24.9 is normal, less than 18.5 is seen as underweight while 25 to 29.9 is considered overweight. A mark of 30 or above means a person is obese.

Research paper:


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