Can't Lose Weight? Your Gut Bacteria Could Be to Blame, According to Study

No matter how strictly some of us stick to weight loss regimes, we still struggle to drop the pounds—and our gut bacteria could be to blame, according to a small study.

A team of researchers at the Mayo Clinic wanted to understand exactly why some individuals find it harder to lose weight than others, even when they follow the same diet regimes. They hypothesized that gut bacteria could hold the answer.

The number of microbes in and on our bodies—including those in our digestive system—outnumber our own cells by 10 to one. And growing evidence suggests these bacteria can affect our overall health.

Such research could be vital for tackling the obesity epidemic, which affects around 93.3 million adults in the U.S.

The makeup of a person's gut bacteria could make it harder to lose weight, according to a new study. Getty Images

For the study, researchers collected stool samples from 26 individuals between 18 and 65 who signed up for the Mayo Clinic Obesity Treatment Research program between August and September 2013. Successful weight loss was defined as a participant shedding at least 5 percent of baseline weight after following the regime for three months.

Tests on gut bacteria taken from the stool samples revealed that those who failed to lose at least 5 percent of their weight had different types of bacteria than those who found it easier. Specifically, a bacterium called phascolarctobacterium was associated with weight loss, while dialister was found in the guts of those who didn't see the pounds fall away.

The results seemed to suggest that the gut bacteria that make it easier to metabolize carbohydrates play a role in lower weight loss, the authors said.

Dr. Purna Kashyap, co-author of the study and a gastroenterologist at the Mayo Clinic, told Newsweek the study indicates that the rules of weight loss plans may need tweaking based on an individual's gut bacteria, or that the makeup of the person's gut bacteria should be changed before a plan is adopted.

"The potential use is to develop personalized strategies for weight loss based on an individual's gut bacterial makeup rather than using a one-size-fits-all approach," said Kashyap. "The good part is, unlike our genes we can in fact manipulate the gut bacteria by using probiotics and diet."

Related: Why being skinny fat could be just as dangerous as being obese

He continued, "Gut bacteria have the capacity to break down complex food particles that we cannot use and in the process provide us with additional energy, which normally is good for us. However, when we are trying to lose weight, this may then become a hindrance, as suggested by our findings.

"So people need to keep in mind, if they are following a weight loss regimen and in spite of doing everything right are unable to lose weight, this may be because the weight loss program is not the right one based on their gut microbiome," Kashyap said.

Related: Food bacteria could be used to fight gut diseases, new research suggests

The study was published in the journal Mayo Clinic Proceedings. The authors acknowledged that while the results are interesting, the sample size was relatively small and further research is needed to see if the same results can be replicated in the wider population.

And while we await proof that the makeup of our guts can determine the ability to lose weight, Kashyap said that, in any case, we should look after the bacteria that populate our digestive systems.