Gut Bacteria Need a Balanced Diet Too
A few lines of evidence suggest that low or moderate fiber intake may create a more healthful, friendly gut flora.
Bacteria not only need carbohydrates for food, they need other nutrients too: phospholipids for their membranes, amino acids for their proteins, minerals for their enzymes. And well-nourished gut bacteria may be more likely to cooperate probiotically with their host.
This may be a reason that tree nuts are healthful. Almond fats, for instance, have been shown to help probiotic bacteria flourish. The benefits of almonds are lost when the fat content is removed.
If gut bacteria need fats, and if providing fats makes the gut healthier, high-carb, low-fat diets may sabotage the gut by creating a scarcity of nourishing fats for gut bacteria. A low-carb, high-fat diet will create a smaller but healthier— and friendlier— population of gut bacteria.
Jaminet, Paul; Jaminet, Shou-Ching (2012-12-11). Perfect Health Diet (Kindle Locations 3259-3267). Simon & Schuster, Inc.. Kindle Edition.