In addition to helping themselves to energy from the food we eat, gut microbes are essential to the availability of nutrients for ourselves. Gut bacteria help us break down complex molecules in meats and vegetables, for example. Without the aid of gut bacteria, plant cellulose is indigestible.

Gut microbes may also have an influence on our cravings and feelings of being full after eating via their metabolic activities.

The diversity of our microbiota is related to the diversity of our diet, and adolescents trying out a wide variety of foods display a more varied gut microbiota than adults who follow a distinct dietary pattern.