Chubby, but fit, might sound like the kind of excuse overweight people use to keep at the crisps. In fact, there is evidence that — contrary to the mainstream thinking — some overweight people lead long and healthy lives, while some slim, apparently healthy people die prematurely of ‘fat diseases’ such as diabetes and heart disease.
Now doctors appear to have discovered what’s going on, heralding a breakthrough in our understanding of weight and disease: in future, it may not be your weight that matters so much as what’s going on inside your body.
And finding out could involve nothing more than a blood test. What it will mean is that instead of doctors saying being over a certain size means you’re automatically ‘at risk’, they would use the results of this blood test to work out your personal risk.
This could even help identify foods that are problems for you, because of how they affect you in particular.
As one leading expert told us, this ‘is the next big thing in medicine’.
Konstantinos Manolopoulos, a clinician scientist in endocrinology and metabolism at the University of Birmingham, explains: ‘It’s a major step towards personalised medicine — where the aim is to provide customised treatment options for patients.’
Body mass index
For nearly 200 years, BMI (body mass index) has been used as a measure of obesity and health risk. It’s calculated by dividing your weight by your height, and dividing the answer by your height again.
A score of 25 or more means you’re categorized as ‘overweight’ and your risk of developing conditions such as diabetes and heart disease is raised significantly.
But, increasingly, there have been questions raised about the reliability of BMI as a predictor of health because it doesn’t show the full picture.
For example, someone can be at risk of disease, and yet be slim and have a normal BMI — or have no health problems, despite being classed as overweight according to their BMI.
Now U.S. researchers say they have developed a replacement, an advanced blood test that may provide a more accurate method of identifying our risk of diseases.
The new approach is based on a study of the health records of around 2,000 people that had been monitored for an average of 13 years.
The U.S. scientists looked at their BMIs and genes, and the levels of around 1,000 compounds in the blood — such as fatty acids, sugars, hormones and vitamins — and how these changed over time.
What they found, though, was that there was a pattern which could predict each person’s risk of developing obesity-related diseases later on.
People who had a specific pattern in their metabolome — which the scientists called the obesity ‘signature’ — at the start of the study were significantly more likely to be obese or end up with diabetes or heart disease by the end of the follow-up period.
They were also more likely to have accumulated fatty tissue in the liver or around internal organs — known as visceral fat — which releases toxic chemicals.
Surprisingly — and this is significant — these problems occurred later in life regardless of the person’s body weight. Some people who were slim but had the abnormal metabolome pattern at the start of the study also developed diabetes or heart disease.
Meanwhile, some obese people in the study had a normal metabolome and didn’t develop these conditions.
The abnormal metabolome could explain why some slim people develop certain conditions such as high blood pressure, diabetes and cardiovascular disease, and why some obese people live long, healthy lives without illnesses, the researchers concluded.
The study supports the existence of the so-called ‘healthy obese’, where some people who are obese can live free from diseases you might expect them to develop.