Gas and flatulence are one of the unpleasant (and fragrant!) aspects of refeeding and re-introducing your body to the digestion process. I always referred to it as the Basset Hound Stage, because I always wanted a dog to blame the smell on. Thankfully, this past summer wasn't nearly as bad as the other times- at least in that respect. As for the reasons why I turned into a veritable gas-passing machine, I just assumed that my digestive tract was a wee bit confused and things weren't being processed as efficiently.

But now I know exactly why.

This probably marks me as a total geek--though what about me doesn't, besides my love of trashy true crime shows--but I was so thrilled to see this research article titled "Monitoring Bacterial Community of Human Gut Microbiota Reveals an Increase in Lactobacillus in Obese Patients and Methanogens in Anorexic Patients."

I know, I know--huh? Well, stand back, kids. I'm a professional!
::insert trumpets here::

What are "methanogens"? They're bacteria that live in your gut and, as they break down your undigested food, they release methane. What is methane? You guessed it- methane is fart gas. Well, okay, it's more than that, 'cuz my organic chemistry professor told me so, but it's also the major gaseous component of farts. (Why am I getting the feeling that this post is going to greatly increase the popularity of "ED Bites" amongst pre-pubescent boys?)

In the study, anorexics had higher numbers of methanogens than normal weight controls. The particular bacterial species that the authors found to be increased in the guts of anorexia patients was Methanobrevibacter smithii, of which Wikipedia says this:

"[M. smithii] is important for the efficient digestion of polysaccharides (complex sugars) because it consumes end products of bacterial fermentation."

Anorexia results in a negative energy balance (by definition), through decreased intake, increased exercise, or both. As such, there will likely be fewer complex carbohydrates available in the gut. The authors of the study concluded the "increase might represent an adaptive use of nutrients in this population." Translation: methanogens help extract more calories from an already limited intake, thus getting more bang for your calorie buck.

The authors didn't subtype the AN patients, which may have made a difference in the composition of bacteria. I would imagine this would be especially so in those who abuse laxatives. It would also be interesting to see how gut bacteria changes during recovery. I think this is an under-explored area, and I would love to see more of this research.