In this study, researchers at the University of Birmingham analysed data of millions of British patients between 1995 and 2015 to see if this claim held true.
They tracked people who were obese at the start of the study (defined as people with a body mass index of 30 or more) who had no evidence of heart disease, high blood pressure, high cholesterol or diabetes at this point.
They found these people who were obese but “metabolically healthy” were at higher risk of developing heart disease, strokes and heart failure than people of normal weight.
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This makes it difficult for scientists to see how clear-cut the conclusions are or gauge how big any increased risks of ill-health might be.
Does everyone agree?
Other studies suggest it might just be possible to be fat and have the right genes, for example, to remain fit.
For example research published in 2012 appears to suggests it is possible for people to buck the trend and be fat and healthy if they have no metabolic diseases.
Published in the European Heart Journal, researchers suggest people who are obese yet physically healthy are at no greater risk of heart disease or cancer than people of normal weight.
Read more: http://www.bbc.co.uk/news/health-39936138