Do these bacteria make my thighs look fat?

Believe it or not, you have a bacterial infection in your intestines right now. And it's OK. We all have bacteria in our guts, ones that live with our bodies in a mutually beneficial (or "symbiotic") relationship. We provide a nice, safe, warm environment, and in return they help us digest our food. There are certain foods that we just couldn't digest without our helpful little microbes, and certain proteins, amino acids, and other nutrients we need that we would have a hard time absorbing if they weren't preprocessed.

Now it appears that they may also influence how well we absorb sugars and store them...and when we store sugars, we store them as fat. Researchers at Washington University inoculated germ-free mice with different microorganisms or a combination of microorganisms and measured how they digested their food. The mice given the combination of bugs digested the sugars within their feed more efficiently, but instead of burning them off, the mice stored them as fat, causing them to gain more weight.

The researchers look at the study as a "logical extension of the human genome project - one designed to define the microbial side of ourselves." They even managed to drop the word "microbiome." (Add that one to the list.)

The take home message? While dieting and exercise are still the best ways to lose and control weight, the bugs in your gut may have something to say about it. The researchers hypothesize that one day treatments that alter the microbial composition of our intestines could be a vital aspect of nutritional control.

[Many thanks to EurekAlert and LiveScience.]