New research finds that dietary sacrifices tell, giving up pizza and hamburgers in favor of a healthy, low-calorie diet may be for naught if your intestinal flora are out of whack from a lifetime of eating a standard American diet.

The study, published last week in the publication Cell Host& Microbe, finds that switching from a diet high in calories and processed foods to a plant-based diet may not be very effective( at the least initially) if there is still an overgrowth of unhealthy bacteria in the gut. This is because the microbiota already living in your intestine determine how well you absorb and processes nutrients, which can affect weight loss, digestion and overall health.

But it’s not all bad news. Over time, a healthy diet will lead to a healthier microbiome it simply may take longer than you’d like.

“If we are to prescribe a diet to improve someone’s health, it’s important that we understand what microbes assistance control those beneficial effects, ” Dr. Jeffrey Gordon, a biologist at Washington University in St. Louis and senior writer of the paper, said in a press release. “And we’ve procured a style to mine the gut microbial communities of different humen to identify the organisms that help promote the effects of a specific diet in ways that might be beneficial.”

The gut microbiome the community of trillions of bacteria living in the digestive tract plays a significant role in the health of the digestive, nervous and immune systems, among other biological systems. These microbes can either aid or prevent weight loss. Diet is one of the main lifestyle factors influencing the makeup of bacteria in the gut, and research has shown that even short-term dietary changes( switching to either a meat-based or plant-based diet) can alter the gut microbial community.

A Tale Of 2 Microbiomes

For the study, the researchers first compared fecal samples of people who followed a calorie-restricted, plant-based healthy diet with those of people with a high-calorie, standard American diet.

As expected, they found that those with the standard American diet had less diverse microbiota, and that people with a plant-based diet had a more diverse( and therefore healthier) microbiome. A diverse bacterial community is beneficial because it helps with digestion, nutrient absorption and immune system function, while an unhealthy microbiome can contribute to inflammation, anxiety, depression, poor digestion and even autoimmune diseases.

Next, the researchers colonized groups of mice with human gut bacteria using the fecal matter samples. The mice was later fed either the native diet of their human donor, or the opposite diet.

Analyzing the microbial communities of the mouse revealed that the gut bacteria of both groups of mice changed in response to their new diets. However, the mouse with the bacteria of the American diet indicated a weaker response to the plant-based diet their microbial communities didn’t increase and diversify as much as the mice colonized with the bacteria of the humans who eat a plant-based diet.

The researchers did find a way to improve the response of the mouse to plant-based diets. When the American-diet mice were co-housed with the plant-diet mice, some of the microbes from the plant-based mice stimulated their style into the microbial community of the mouse with the less healthy intestine bacteria. With the addition of the bacteria from the plant-based mice, the American-diet mice presented a stronger response to their new, healthier diet. It’s not clear whether bacteria in humen can be transferred from others in the same way.

“Many of these bacteria that migrated into the American diet-conditioned microbiota were initially absent in many people devouring this non-restricted diet, ” study author Dr. Nicholas Griffin said in a press release.

All of this isn’t to suggest that your intestine won’t is beneficial for a plant-based diet it only may take a little longer than you’d hope to see outcomes. Dietician Meghan Jardine told The New York Timesthat adopting a more plant-based, high-fiber diet is probably the best way to build a healthier microbiome.

“When you look at populations that eat real food that’s high in fiber, and more plant-based foods, you’re go to they have a more robust microbiota, with more genetic diversity, healthier species and fewer pathogenic bacteria living in the gut, ” Jardine said, according to the Times.

Managing stress levels, eating more fermented foods and exercising also can help boost the different levels of healthy bacteria in the gut. If you follow a gut-healthy lifestyle, your bacteria will catch up soon enough.