In a meta-analysis in Biobiology, researchers from the University of California, San Francisco, Arizona State University and the University of New Mexico concluded that these microbial communities can influence the host's eating patterns through the vagus nerve. Vagus nerve is a nerve extending from the brain to the intestine, and microorganisms like to play with it.

Intestinal flora controls the host's eating pattern in order to survive and reproduce, and also to eliminate the microbial competitors next door. Intestine is the battlefield of these bacteria, and manipulating the host brain to ingest specific foods is their main weapon. Sometimes they even endanger the host by making it eat harmful food. Studies have found that people with insufficient intestinal flora diversity (that is, one bacteria kills all other bacteria by manipulating the brain) are more likely to be obese.

The paper emphasizes that intestinal flora is not the only factor of obesity, but the author does find that some studies show that microbial flora may be contagious, including those bacteria that lead to overeating.

Then why not immediately use a bunch of antibiotics to give those bacteria in our intestines a genocide? Well, the paper explains that these microorganisms have important functions such as "nutrient intake and immune development", that is, they provide us with vitamins and minerals and build our immune system in exchange for survival in our bodies. These microbial communities also help the host digest certain foods. People living in Japan have a special kind of bacteria to help them digest seaweed. Some African children who eat sorghum stalks have bacteria that can help them digest cellulose.

Fortunately, however, everyone's microbiota can be easily controlled by relatively simple changes in eating habits.

If you are worried about the composition of your microbial community, please understand that it may only take a few minutes to change it through diet-this is the time required for the evolution of your intestinal microbial community, and it is only 24 hours-this is the time required for the intestinal microbial community to rebuild itself after diet change. Changing the bacteria in the intestine may help to change the eating habits, and vice versa.

"Because people can easily manipulate the microbial community by using prebiotics, probiotics, antibiotics, fecal transplantation and dietary changes, changing the microbial community provides us with an easy-to-operate solution to solve problems that are difficult to solve by other methods, such as obesity and unhealthy diet." The author wrote in a statement.

In addition to making life healthier, "taking action on microbiota may also prevent and treat many diseases, including obesity, diabetes and even gastrointestinal cancer," said Acti Pease. "We are just beginning to understand the importance of microbiota to human health."