Low-fiber, high-fat diets cause significant shifts in the gut microbiome

Changes to gut microbiome are known to impact metabolic health. Physiologists at Laval University in Canada have discovered that diets containing low fiber and high fat cause significant shifts in the gut microbiome-;the collection of bacteria, viruses, fungi and other multicellular microorganisms that live in the gastrointestinal system. The study is published in the American Journal of Physiology-Gastrointestinal and Liver Physiology. The research paper has been chosen as an APSselect article for June.

Researchers used a mouse model to determine the key dietary factors affecting gut microbiome and how they contribute to obesity and other metabolic diseases like type 2 diabetes. Mice were fed varying levels of low-fiber, high-fat diets which changed their gut microbiome.

What we have shown is that by increasing the amount of fiber in your diet and lowering the amount of fat, you work on two very important components that will improve your health."

André Marette, PhD, Laval University, Canada

Marette talked more in-depth about his findings in this video interview.

60ca23536e7a6_Dr Andre Marette Intvw.mp4

More than 34 million people in America have diabetes, and the overwhelming majority of these individuals have type 2 diabetes, according to the U.S. Centers for Disease Control and Prevention. Marette's team hopes to test the findings from the animal model in a new upcoming clinical study involving humans. The goal is to help define novel nutritional approaches to prevent unhealthy changes in gut microbiome and intestinal function to reduce the risk of metabolic diseases.

Read the full article, "Dietary fat and low fiber in purified diets differently impact the gut-liver axis to promote obesity-linked metabolic impairments." It is highlighted as one of this month's "best of the best" as part of the American Physiological Society's APSselect program.

Journal reference:
  • Daniel, N., et al. (2021) Dietary fat and low fiber in purified diets differently impact the gut-liver axis to promote obesity-linked metabolic impairments. Journal of Physiology-Gastrointestinal and Liver Physiology. doi.org/10.1152/ajpgi.00028.2021.


  1. Dorin M Dorin M United States says:

    He's an idiot.   High fat, low fiber and of course little to no carbs (20 grams or less) does not lead to obesity or type 2 diabetes.   As scientists or researchers, they're not looking for evidence of fact but more so to prove a belief and disposition they already believe. Talk about disingenuous behavior....

  2. Emily elk Emily elk United States says:

    I am so sick of these types of studies popping up and putting out misinformation. It drives me absolutely crazy.. mice are helpful but they are not humans and making dietary recommendations for humans based on mouse studies is a joke. We know for a fact that people all over the word are using a ketogenic or carnivore diet to REVERSE diabetes. Yes, it is anecdotal but this does not mean that it is not happening or that we should dismiss it. It is just overwhelmingly frustrating. I do not have access to the full study so I can not see what they fed the mice but I am sure that just like in other studies like this one, they used plant  oils as the fat which in incredibly inflammatory, and they probably did not exclude carbohydrates which, when combined with fat causes metabolic dysfunction.. The biggest issue though, is that mice are herbivores. They are opportunistic and will eat anything including non food items, but they are obligate plant eaters. You do not have to look any further down their digestive tract than their teeth to know for certain that they were not intended to eat the same diet as humans. It would make sense that a herbivore's microbiome thrives on fiber.
    We also know for a fact that certain bacteria that we know live in the human gut, will not survive in the gut microbiome when transplanted. This tells us without a doubt that their microbes are not the same as ours! In another study where mice were fed a diet without fiber, their gut microbes consumed the protective mucus lining in their gut. They try to use that study to tell humans that they should eat more fiber or their gut will suffer but we know this is not true because of all of the people on the carnivore diet who regain their health by eliminating fiber!
    What is going on here? Why are they wasting money on these studies when we need well done human trials so that we can put this false information to rest. This all makes me wonder who is paying them to do these studies and put out this information because it seems as if they do not actually want people to get well.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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