Our ancestors had a vastly different diet than the one we have today. They had a much higher fiber content in their diet with less meat. This earlier human diet led to greater diversity of gut bacteria, which we now understand is important for health. Considerable research is being done worldwide about which bacterial populations will be best to consume as probiotics (live bacteria believed to aid health and enhance bacterial populations in the gut). Consumption of yogurt which has live bacteria is desirable, but don’t eat yogurt with a lot of sugar. Rather than eating yogurt with added fruit and sugar, it’s better to eat plain yogurt and add your own fruit. Prebiotics are non-digestible fibers that cannot be digested by people, which are designed for their ability to be metabolized by desirable gut bacteria. Consumption of high-fiber foods (including fruits, nuts, legumes, brown rice, beans, whole grains, vegetables, whole wheat bread) will have a similar effect on the microbiome as prebiotics. It is wise to avoid low-fiber foods such as red meat, which is high in saturated fat and provides little of the nutrition which is needed by our microbiota.