It’s well-known that our diet can have a big influence on the health of our gut, but did you know it can make lasting changes in as little as three days? It’s true! In fact, the life span of a microbe is about 20 minutes, so a lot can happen in three days.
The three-day rule came from a groundbreaking study published in the journal Nature that showed that when 10 people drastically changed their diet, by day three they had made significant changes in the type of bacteria and the number of bacteria in their GI tract. The changes were not subtle; they saw not just a variation in the types and amounts of bacteria but also in the kinds of genes they were expressing.
In the same study, they also found that food-based bacteria (in fermented or aged food) was surprisingly resilient, making it all the way to the gut to influence the microbial environment. This study, along with many others, shows that if we drastically change our diet, we can drastically change our gut bacteria.