Scientists have found a strange way of determining details of how much dangerous fat we are likely to have in our bodies – through studying the bacteria found in our excrement.

A team of researchers from Kings College London studied and analyzed stool samples from more than 3,600 twins to find out if the amount of fat we carry around is really inherited. What they were primarily looking at was human faecal microbiome – the bacteria found in our excrement – and how much of it and how diverse the bacteria were.

Samples of stools were compared to six different measures of obesity such as the BMI index to see if there was any link and using X-ray to measure amounts of fat throughout the body. Interestingly, they found that visceral fat (the most dangerous and unhealthy kind) was less in people who had a higher diversity of microbiome and more in people with less diversity, according to a BBC report.

“The key thing we found in our work is that the associations with the microbiome are much stronger with visceral fat than with any other measure of obesity,” says Michelle Beaumont, a research associate at the department of twin research at Kings College. “And because visceral fat has a lot of implications for heart disease and metabolic diseases, maybe studies should start looking at the actual measurement of fat rather than measures that are as broad as BMI.”

Further studies will be made to find out whether changing a person’s individual bacteria ‘make-up’ in their poop can affect their overall weight. Either way, this new discovery will hopefully pave the way to find out ways to control weight and understanding what contributes to obesity.

The study was published in the journal Genome Biology.