Let’s address dietary fiber. As long as I can remember, fiber has been marched around as an essential component of a healthy diet. The supposed benefits of a high-fiber diet have been hammered at us by our doctors, government, and the food industry – all those annoying cereal commercials come right to my mind – many of these health claims have nothing solid (no pun intended) to back them up (ok, so maybe a little pun fun 🙂 ). In fact, many studies have demonstrated that excess intake of fiber may actually be harmful and lead to more gastrointestinal issues than any “benefits” found.
The majority of the research supporting the benefits of dietary fiber come from epidemiological (medical speak for “the study of diseases”) studies that link the consumption of fiber-rich fruits and vegetables with a lowered risk of certain diseases such as obesity, heart disease and cancer, particularly colon cancer. Yet when tested in the lab, controlled intervention trials that added fiber to an otherwise consistent diet have not shown this to be true. The recommended daily fiber intake is 38 grams for men and 25 grams for women, which may come from dietary fibers, both soluble and insoluble, or the addition of functional fibers to the diet. Functional fibers are non-digestible carbohydrates that have been isolated or extracted from a natural source, or they may be manufactured\synthetic. Examples of functional fibers are psyllium husks, fructooligosaccharides, polydextrose, and soluble corn fiber. These functional fibers are often added to foods as a way to bulk up the fiber content for consumers looking to meet the intake guidelines. Three grams of added fiber is enough to allow these food products to claim to be a good source of fiber.
Tan and Seow-Choen in 2007 penned a piece on fiber and colorectal disease. In this article, they discovered excess insoluble fiber can bind to minerals such as zinc, magnesium, calcium, and iron, preventing their absorption and having them instead be passed out of the body as waste. WHOA. Stop the presses!! What? All these minerals that we need and supplement when being keto are being banged out the back end because of fiber? Lovely. Wait, there’s more!! Large excesses of certain soluble fibers like pectin and guar (both very common binders\gums used in low carb products) may also inhibit pancreatic enzyme activity and protein digestion in the gut. HOLY BAD MEDICINE, BATMAN!! In layman terms, that means that fiber – long touted to be great for lowering blood sugar, cholesterol, and maintaining healthy (if you aren’t the one cleaning the bathroom, of course…) lifestyle, in reality, is blocking your ability to properly use protein, break down other nutrients, and forcing important minerals out instead of in.
A high-fiber diet has also been described as a preventative strategy for the development of diverticulosis. DIVERTICULOSIS is when pockets called DIVERTICULA form in the walls of your digestive tract. The inner layer of your intestine pushes through weak spots in the outer lining. This pressure makes them bulge out, making little pouches. Diverticulosis may lead to several complications including inflammation, infection, bleeding or intestinal blockage. However, when researchers tested the theory that a high-fiber diet prevented diverticulosis, they not only found that a high intake of fiber did not reduce the prevalence of diverticulosis, but that a high-fiber diet and greater number of bowel movements were independently associated with a higher prevalence of diverticula. Another case of the cure being the cause, so it seems.
What is frightening is that even with these studies and research – just like we see with diabetes and carbs – the recommendations haven’t changed :(. The researchers hypothesized that one possible effect of a high fiber diet in the development of diverticulosis could be the changes in gut bacteria due to the excessive fiber intake. Both insoluble and soluble fibers are shown to alter gut bacteria in as little as two weeks. It is has been hypothesized (additional research is pending) that the high levels of excess fiber and overgrowth of intestinal bacteria may have contributed to the development of diverticular pouches in the colon, the opposite of the intended results and in direct opposition of the previously thought science that the bacteria was helpful.
So, what does this mean for you? Like I try to express in every post – learn what your body likes and doesn’t like. Don’t take sweeping statements – in either direction – as gospel until you know yourself. This is why induction is CRITICAL, followed by careful addition of ketofied foods. Watch and TRACK what you eat, how you feel after you eat, and what your body is telling you from what you put into it.