Body Mass Index: The Healthiest Body Weight Is Actually Different From What You Think

There is currently only one index used to calculate whether someone has a healthy weight or not: the Body Mass Index (BMI). This index has six different categories ranging from 'extremely obese' to ‘underweight' and people often turn to this index to analyse whether they are healthy or not.

Criticism of this index

But for a few years now, this index has been strongly criticised by scientists and its reliability has also been called into question.

‘This should be the final nail in the coffin for BMI,’ claimed Dr. Jeffrey Hunger. This researcher from the University of California did not participate in the recent Danis study, but has been looking into the matter for a long time.

In the recent publication published in the JAMA Network journal, researchers at the University of Copenhagen came to the same conclusion. It is urgently necessary to update our knowledge and definition of the BMI.

Long-term Danish study

They collected data from 100,000 Danish adults over a 15-year period over the course of this study and the results were clear. People who are defined as 'overweight' according to the BMI scale had a longer life expectancy than those who fell under the category of normal, underweight and obese.

As these researchers calculated, the BMI associated with the lowest risk of death actually increased between 1976 and 2013 from. 23.7 (‘ideal weight’) to 27 (overweight’). In other words, the weight category associated with the highest life expectancy has changed from ‘healthy’ to ‘overweight' over the last 40 years!

Context is key

But one thing remains clear to scientists, our definition of the BMI needs to be updated.

'BMI as a number alone may not be sufficient to predict health and risk of death,’ as Dr. Rexford Ahima, who was also not involved in the study, has claimed.

‘It has to be taken within context,’ he says. This includes factors such as age, gender, genes, socio-economic status and possibly also tobacco consumption.

47% of ‘overweight' people are actually healthy

Due to the BMI's lack of reliability, 47% of the people who fall into the ‘overweight' category are actually quite healthy, as Jeffrey Hunger explains.

One of the reasons for this is that the risk factors associated with weight gain, such as an elevated cholesterol level or high blood pressure are much easier to treat than they were 40 years ago.

Don’t forget to exercise

But that doesn’t mean you should just cancel your gym subscription and get fries in the canteen whenever you feel like it. As researchers state, the best way to be healthy is still by following a healthy diet and getting regular exercise.

Obesity is simply an issue that concerns society and even celebrities have been talking about this more and more recently. Take Sam Smith for example, who recently broadcasted an important message for everyone who, like him, is unhappy with their weight.