^ Greenberg CR, Dilling LA, Thompson GR, Seargeant LE, Haworth JC, Phillips S, Chan A, Vallance HD, Waters PJ, Sinclair G, Lillquist Y, Wanders RJ, Olpin SE (April 2009). "The paradox of the carnitine palmitoyltransferase type Ia P479L variant in Canadian Aboriginal populations". Molecular Genetics and Metabolism. 96 (4): 201–7. doi:10.1016/j.ymgme.2008.12.018. PMID 19217814.
Those issues can be part of what's known as the “keto flu,” Warren says. Other side effects of the keto diet, all of which are tied to carb withdrawal, can include lightheadedness, nausea, mental fog, cramps, and headaches, in addition to tiredness. Luckily, the keto flu doesn't usually last more than a week—which is coincidentally about when people start to see the number on the scale go down, says Warren.
C8 is the rarest MCT found in coconut oil, comprising about 6% of coconut oil. It has potent anti-microbial properties (way more potent than lauric acid) to help you maintain a healthy gut, and it is the fastest MCT to metabolize in the brain. (hence the name Brain Octane). Your liver does not need to process C8, and it only takes the steps for your body to turn it into ATP cellular energy (sugar takes 26 steps). You would need 18 tablespoons of coconut oil to get just one tablespoon of Brain Octane.
Other causes of diarrhea on the keto diet include consuming a diet low in fiber (fiber helps ward off diarrhea by bulking up stool) and eating processed low-carb foods like shakes and bars that may contain sugar alcohols. These sugar alcohols can ferment in the gut and cause gastrointestinal discomfort. Yawitz suggests limiting foods labeled “sugar free” if you’re prone to gas or diarrhea when you eat them. And you may want to gradually adjust your carbs downward and your fats upward. “Also build your diet around [naturally] high-fiber, low-carb foods like avocado and nonstarchy vegetables such as broccoli, cauliflower, and asparagus,” she says. Other keto-friendly ways to get more fiber include chia seeds, almonds, and coconut.
^ Jump up to: a b c d e f g h i j k l m n o p q r s Kossoff EH, Zupec-Kania BA, Amark PE, Ballaban-Gil KR, Bergqvist AG, Blackford R, et al. Optimal clinical management of children receiving the ketogenic diet: recommendations of the International Ketogenic Diet Study Group. Epilepsia. 2009 Feb;50(2):304–17. doi:10.1111/j.1528-1167.2008.01765.x. PMID 18823325
“Muscle loss on the ketogenic diet is an ongoing area of research,” says Edwina Clark, RD, a dietitian in private practice in San Francisco. “Small studies suggest that people on the ketogenic diet lose muscle even when they continue resistance training. This may be related to the fact that protein alone is less effective for muscle building than protein and carbohydrates together after exercise.” Meanwhile, according to a small study published in March 2018 in the journal Sports, people following the keto diet for three months lost about the same amount of body fat and had about the same muscle mass changes as people following normal diets. Yet the folks on keto did lose more leg muscle.