Germs in your gut may help drive appetite, says new research into the link between obesity and bacteria.

Previous studies have shown that overweight people and normal-weight people harbor different types and amounts of microbes that naturally live in the intestine. To determine why, scientists are peering into mice.

Researchers transferred bacteria from the fat mice directly into the germ-free intestines of normal newborn mice.  Those mice began eating more and developed inflammation and insulin problems.