When we add in the ketogenic diet, things start to slow down even more. Constipation is a well-known side effect of the ketogenic diet. The classic ketogenic diet has approximately 90% of its calories coming from fat. Fat moves through the body at a slower rate than other nutrients. This can be advantageous because it can keep one fuller for longer, but it also slows down digestion leading to constipation. Even the Modified Atkins ketogenic diet, which has around 60-70% of calories from fat, can cause the body’s digestion to slow down significantly too. Additionally, the ketogenic diet may be lacking in fiber due to low carbohydrates and low fruit/vegetables in the diet. However, there are some keto-friendly fiber foods, which will be discussed later in this article.
One of the best ways to help prevent constipation is hydration, hydration, hydration – meeting or exceeding one’s fluid needs is an absolute must! Talk to your dietitian for your child’s specific fluid goals. Another way is with movement! Talk to your physical therapist for specialized movements for constipation specific to your child. Because of the addition of the ketogenic diet, medication may also be necessary to help with gut regularity especially for tube-fed patients.
There are two main categories of medications that help constipation: the ‘Mushers’ and the ‘Pushers’. The ‘Mushers’ are a group of medications that helps draw water into the stool making it easier for stool to pass through the colon (also known as osmotic laxatives). The most common keto-friendly “musher” is MiraLAX® (polyethylene glycol 3350) and is typically the first line of treatment. Some side effects may include looser and/or more frequent stools. It’s a flavorless powder that can be easily added to water flushes/drinks throughout the day (2). Another ‘musher’ is Milk of Magnesia (also known as magnesium hydroxide or citrate). It also works by helping draw water into the stool. Like MiraLAX®, common side effects include looser and/or increased frequency of stools. Lactulose is another ‘musher’ but not typically used on the ketogenic diet due to possible carbohydrate content.
Insoluble fiber is an honorary musher as well. It acts in the digestive system by bulking and softening the stool because it is not dissolvable in fluids. Instead, insoluble fiber absorbs fluids in the gut and sticks to other waste materials to make softer stool. Fiber can be harder to consume on the ketogenic diet because most sources are high in carbohydrates. However, nuts, cauliflower, green beans, carrots, and berries can fit into the ketogenic diet. Another interesting food that contains 85-93 % insoluble fiber is chia seeds. Chia seeds also have an impressive lipid content, therefore, depending on the brand, chia seeds are ~1:1 ketogenic ratio and may fit into your child’s ketogenic diet (3).
