People blame rapid weight gain on a great many causes, including the stress of a new job, smoking cessation, and plain old genetics. One woman points to a fecal transplant from her daughter as the reason she gained 36 pounds in a short period of time, making her officially obese. Doctors think there may be a link between bacteria in the gut and obesity, but they don’t completely understand it yet. Could this new medical procedure be making people fat?

uk woman obese after fecal transplant

Fecal transplant is a new but totally valid medical procedure intended to introduce healthy bacteria into a patient’s intestines, in an effort to treat a host of maladies. Many patients of the procedure suffer from an infection due to an overgrowth of ‘bad’ bacteria like Clostridium difficile in the digestive system, which sometimes can’t be treated by antibiotics. Although the infection itself isn’t fatal, the patients are often so sick that their quality of life is greatly diminished, and they can become susceptible to other illnesses.

Related: Researchers find a new way to beat antibiotic-resistant infections

The 32-year-old British woman was plagued by one of those infections, and had suffered terribly prior to the fecal transplant. Doctors identified her daughter—or rather, her daughter’s stool—as the best course of treatment. The woman’s daughter was already overweight and on her way to becoming obese, but doctors didn’t anticipate that the mother would have such a drastic change in body chemistry as a result of the treatment.

After the transplant, the patient’s persistent infection did clear up—for about a year. Unfortunately, she suffered an unexpected “side effect.” Her Body Mass Index (BMI) spiked from 26 to 34.5 in just three years, and she complained of rapid weight gain. Her infection also returned.

In lab research, fecal transplant experiments in mice suggested the possibility of transferring the tendency for obesity. Doctors familiar with the procedure aren’t ready to say that all patients will experience the same results as this woman, but they are getting a little nervous about the power of poop. Dr Colleen Kelly, from the Medical School at Brown University, said after studying this case that she would avoid using obese donors in the future. However, some doctors may simply consider it a trade off, thinking that it’s better to be fat than sick.

The latest in the long list of things you can do with poop.


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