A study just came across my desk that isn’t new but sheds light on some of the inconsistencies of research on “high fat” and “Western diet” effects on gut microbes.
Much of the mechanistic work on how diet affects physiology and microbes is done with mice. Studies from mice reliably show deleterious effects of high fat diets on cardiometabolic markers and microbe populations.
The researchers noted that when (other) researchers compare high fat diets with the mice’s usual fare (rodent “chow”), the high fat diet had significantly less fiber in it.
For the study, mice were given either low fat/low fiber or high fat/low fiber. Both groups had substantial changes in their microbe populations compared to the normal diet, regardless of the amount of fat.
Given that human diets that are high in fat tend also to be low in fiber, the findings suggest that some (much?) of the deleterious effects of the “Western Diet” on gut function and other outcomes may be due to the lack of fiber as well as the excess of fat. So just another reason to keep an eye on fiber.