While we've been hearing more and more that fat is not the enemy, there are many that continue to reach for studies that have not been properly designed, as proof. Some of these studies which cite that fat can significantly reduce the gut microbiotoa, only focus on fat as having an effect on gut health. However, we really need to question the type of fat we are talking about.
Study design that wants to have an outcome that shows that fat is indeed going to lower gut flora, will not mention the types of fats individuals are eating. If we're talking about eating McDonald's, fried and processed foods high in vegetable oils and overly processed meats etc, then I'm going to 100% agree that, eating this way will negatively impact the microbiome. But what about the individuals who are consuming grass fed meats, good quality sources of fat from nuts, seeds, avocados and healthy olive and coconut oils, while consuming ample amount of fermentable fiber from vegetables and fruits?
This is where nuance comes into play. We cannot lump it all into the fat category. This is why designing nutrition studies with humans is going to be a challenge. Subjects cannot be kept and observed for something like 5-10 years to see the changes their bodies go through long term. But what we can do is at least publish data correctly and ensure that some of these nuances are not left out as they can make or break a paper and in turn influence how studies are interpreted by the masses.