We have the benefit of plenty of clinical observations of the results of ketogenic diets because thousands of children with epilepsy have been put on these diets to reduce the frequency of grand mal seizures that are poorly responsive to antiseizure drugs. Ketogenic diets have been used for this purpose since the 1920s and can reduce seizures by as much as 50 percent or more—no question: they work. Earlier experiences, unfortunately, upped the children’s fat intake that is required to maintain ketosis by supplementing with substantial quantities of corn oil, which, by itself, results in unhealthy consequences (e.g., increased intestinal “leakiness” to bacterial breakdown products, excessive oxidation upon heating). That practice has been abandoned, however, and kids now obtain higher fat intake with medium-chain triglycerides (MCTs), coconut oil, fatty meats, olive oil, and butter.
Many of these children on the ketogenic diet have been studied, and it’s been observed that they develop kidney stones (which children otherwise rarely experience), osteopenia (bone thinning), impaired growth, and cardiomyopathies (impaired heart muscle that can lead to heart failure). The same sorts of changes in bowel flora occur in both children and adults on strict low-carb diets, and these changes are associated with constipation and increased potential for diverticular disease.
The lack of prebiotic fiber has been shown to trigger proliferation of bacterial species such as Akkermansia muciniphilaand others, as discussed in Chapter 5, that have the unique ability to exist exclusively on human mucus. In other words, when deprived of prebiotic fibers, many bacterial species die or diminish in numbers, while Akkermansia thrives and overproliferates by consuming human mucus. This deteriorates the mucus lining of the intestines, allowing entry of bacteria into the intestinal wall along with intestinal inflammation and increased endotoxemia that then exports inflammation to other parts of the body. People typically experience the consequences of inadequate prebiotic fiber intake as increased levels of triglycerides, increased insulin resistance and high blood sugar, and increased blood pressure, changes that undo the initial beneficial effects of a low-carb diet.
Bottom line: Sure, limit your carbs, especially the most offensive to health of all: wheat, grains, and sugars. But be mindful of your prebiotic fiber intake to ensure that you are feeding your garden of happy microbes.