Could an exchange of poop from a slim person help an obese individual lose weight? We could soon find out, as scientists in the U.S. are embarking on a clinical trial to find out whether so called “fecal microbiota transplantation” (FMT) can aid weight loss.
Hearing the term “fecal transplant” may leave you with some tense glute muscles, and yes, the procedure can involve exactly what you’re thinking (a poop enema, in case you’re unimaginative). But this upcoming trial, led by Dr. Elaine Yu from Massachusetts General Hospital, will involve taking freeze-dried poop that’s been popped in a pill. We’ll let you decide which is the lesser of these two evils.
There is, of course, method behind the madness. The microbes in our gut, collectively called the gut microbiome, play a whole host of roles in the body, from helping us break down food to influencing our metabolism, mood, and even behavior. And in recent years, the possibility that they could also shape our body composition has been on scientists’ radars. With obesity a worsening worldwide crisis, the idea is certainly worth investigating, and studies have churned out some fascinating results.
A few years ago, scientists looked at pairs of twin mice that were discordant for obesity, meaning that one was lean while the other was overweight. Giving germ-free rodents gut microbes from the overweight mice caused them to gain weight and fat, and resulted in shifts in metabolism towards those typically associated with obesity. But what was most interesting was that buddying up mice containing an obese twin’s microbes with cage mates harboring germs from the slim sibling actually prevented the former from gaining weight.
That’s perhaps not the strangest story, though. Early last year, a case report appeared in which a woman rapidly became obese following a fecal transplant procedure, for which her daughter was the donor. Although her daughter was borderline normal in terms of BMI at the time, she shortly tipped onto the overweight side after the transplant. While it couldn’t be confirmed that the bacteria contained within the daughter’s feces were to blame, the team concluded that the transplant was at least partly responsible. An unfortunate consequence, though the transplant did do its intended job: treating a recurrent bacterial infection.
So it seems there’s enough evidence to justify examining this potential link between the gut microbiome and bodyweight further. Due to start in March this year, the trial is anticipated to involve roughly 20 obese participants who will be randomly assigned either poop pills from slim donors, or placebos. Over 12 weeks, researchers will document any changes in weight alongside other secondary measures such as body composition and insulin resistance, the latter of which is commonly associated with obesity.
Importantly, the team will also collect stool samples and look for any alterations in its microbial composition. Some species of bacteria have already been implicated in obesity, so it will be interesting to see whether the same organisms appear significant in this trial.