ARE ANTIBIOTICS MAKING US FAT?

The past five years have seen interest in the idea that our gut bacteria play a crucial role in regulating weight, and killing them off with antibiotics is causing obesity.

The most recent evidence is fascinating but inconclusive. Studies in prestigious medical journals have produced contrasting results. One found that three courses of antibiotics before the age of two was associated with increased risk of early childhood obesity, while the other found that exposure to antibiotics in the first six months of life was not associated with early childhood weight gain.

Yet recent research is indicating a link between gut fauna and our body mass index. People with higher levels of Christensenellaceae bacteria – one in 10 of us – appear less likely to put on weight than those with lower amounts. Scientists from King’s College London have found that levels of this bacteria are partly genetically determined.

According to Yeo, who investigated the possibility of microbial transplants to cure obesity for a BBC programme, this new field is important and requires research. “But I have yet to see convincing evidence that there are lean bacteria and obese bacteria,” he says.

Verdict: More research needs to be done, but our gut bacteria may affect how readily we put on weight.