Here's why a healthy diet may not always work

Certain human gut bacteria need to be lost for a diet plan to be successful, said the study that identified the organisms that help promote the effects of a particular diet.

"If we are to prescribe a diet to improve someone's health, it's important that we understand what microbes help control those beneficial effects," said study senior author Jeffrey Gordon from at Washington University in St. Louis. 

"And we've found a way to mine the gut microbial communities of different humans to identify the organisms that help promote the effects of a particular diet in ways that might be beneficial," Gordon noted.

In order to study how dietary practices, influence the human gut microbiota and how a microbiota conditioned with one dietary lifestyle responds to a new prescribed diet, Gordon and his collaborators first took faecal samples from people who followed a calorie-restricted, plant-rich diet and samples from people who followed a typical, unrestricted American diet. 

The researchers found that people who followed the restricted, plant-rich diet had a more diverse microbiota.

In the study, published in the journal Cell Host and Microbe journal, researchers also described how they found a way to mine the gut microbial communities of different humans to identify the organisms that help promote the effects of a particular diet in ways that might be beneficial.

The scientists are optimistic that their approach will help guide the development of new strategies for improving the effectiveness of prescribing healthy diets.

"We hope that microbes identified using approaches such as those described in this study may one day be used as next-generation probiotics," Gordon said.