September 27, 2015

This article originally appeared on MIMI.

By Kelly Bryant

Why is it that certain diets work for some people but feel like abysmal failure? Don't blame your will power, your stomach is most likely to blame. Or, rather, the bacteria inhabiting your stomach.

Before you get grossed out, well all have bacteria in our tummy—it's called our microbiome. A study out of Chalmers University of Technology in Gothenburg, Sweden has concluded that your microbiome influences how your body's metabolism reacts to a diet.

After testing 45 people, researchers found there are two types of five key species of bacteria – a high diversity microbiome and a low diversity type.

The study put participants on the same diet – with a restricted number of calories that was high in fiber and fruit.

"Both groups lost about the same amount of weight, but whereas the low-level group had a pretty bad plasma chemistry before diet intervention, their plasma chemistry was significantly improved. For the high-level group there were smaller changes in plasma chemistry," Jens Nielsen, a systems biologist and the lead researcher on the study, in an interview with Allure. "I interpreted this as meaning that if you have a high level of bacteria it means you can better cope with being overweight and your diverse microbiome levels assist you in metabolizing a high energy or carbohydrate diet."

The hope is that in the future prospective dieters can have their microbiome type detected so that the best plan of action can be applied to their daily nutrition. Additionally, Nielsen hopes that if scientists can dial in on the correct species of bacteria, they may be able to add them to those with a low diversity microbiome to bring them up to the same level as those in the high diversity group.