In two new studies published this week, scientists have gained new insight into how exposure to antibiotics affects the body and may increase the risk of obesity, notably in children.

In one study, published in the journal Nature, researchers from the New York University School of Medicine administered low doses of antibiotics to mice over a period of six weeks.  They found the mice that were given antibiotics gained about 10 to 15 percent more fat mass than the control mice that did not receive antibiotics over the same time period.

The researchers believe this excess fat gain may in part be explained by the antibiotics' effects on the gut microbiome - or community of bacteria in the stomach - as well as the other organs.

They observed that while the antibiotics had no effect on the number of bacteria in the stomach, the medications significantly altered the composition, or levels, of different types of bacteria present.