Antibiotics used to fatten animals may contribute to obesity in humans.

“Farmers have used antibiotics to fatten animals for food production for decades and the world expert on the microbiome Marty Blazer who was the chief of medicine at NYU his daughter developed chronic abdominal diseases and obesity they feel terrible because they gave her a bunch of antibiotics in childhood and they thought there was an association he started he's a laboratory scientist he started doing all these mice experiments if antibiotics are making animals more obese what are they doing to humans that by the way is another one of the Bradford Hill criteria do you have experimental evidence that also supports this which of course in the case of human epidemiology you would you would look at at animals”