MicrobeWorld

The search for factors contributing to obesity has turned inward — all the way to the middle of the gut, where as many as 100 trillion bacteria hang out. The mix of microbes in a given person’s innards may — emphasize “may” — play some role in determining his tendency to put on pounds by governing how efficiently he digests food. (Here’s a 2006 NYT magazine article on this branch of scientific research, and here’s a recent LAT blog post on one such study.)

Research presented today at a meeting of the American Society for Microbiology highlights different aspects of this theory. One study, for example, found a correlation between the presence of one type of bacteria in the guts of women aged 40 to 45 and their body fat percentage. Another study didn’t find any differences between the gut microbes of lean and obese kids, but results suggested the obese kids’ bacteria were nevertheless better at converting food passing through the digestive tract into elements that the body could use — or store in the form of fat.