Let’s talk about a keto side effect that may not be so sexy: constipation. “Many of the richest sources of fiber, like beans, fruit, and whole grains are restricted on the ketogenic diet,” says Clark. “As a result, ketogenic eaters miss out on the benefits of fiber-rich diet such as regular laxation and microbiome support. The microbiome has been implicated in everything from immune function to mental health.” Indeed, in a long-term study in the Journal of Pediatrics in April 2015, constipation was noted as a very common side effect in children receiving ketogenic diets for epilepsy treatment.
Because the ketogenic diet alters the body's metabolism, it is a first-line therapy in children with certain congenital metabolic diseases such as pyruvate dehydrogenase (E1) deficiency and glucose transporter 1 deficiency syndrome, which prevent the body from using carbohydrates as fuel, leading to a dependency on ketone bodies. The ketogenic diet is beneficial in treating the seizures and some other symptoms in these diseases and is an absolute indication. However, it is absolutely contraindicated in the treatment of other diseases such as pyruvate carboxylase deficiency, porphyria, and other rare genetic disorders of fat metabolism. Persons with a disorder of fatty acid oxidation are unable to metabolise fatty acids, which replace carbohydrates as the major energy source on the diet. On the ketogenic diet, their bodies would consume their own protein stores for fuel, leading to ketoacidosis, and eventually coma and death.
This benefit surprised me when I first discovered it, but eating fewer carbohydrates during a workout can actually help you recover from workouts faster. The repair and recovery of skeletal muscle tissue is dependent on the “transcription” of certain components of your RNA. And a bout of endurance exercise combined with low muscle-carbohydrate stores can result in greater activation of this transcription. In other words, by training in a low-carbohydrate state, you train your body to recover faster.
“Given that there is no known detriment to consumption of a high-carbohydrate diet (other than body weight gain due to water retention) and some research reports a benefit, it is recommended that all athletes consume a high-carbohydrate training diet, i.e., at least 60-70% of energy as carbohydrate (7-10 g/kg), and increase this to 65-85% for the few days before competition. Use of a carbohydrate supplement before and during exercise will likely improve performance of intermittent, high-intensity sprints.”
“If you’re going to do keto, there’s a better and a worse way to do it,” says Yawitz. “Loading your plate with meats, and especially processed meats, may increase your risk for kidney stones and gout,” which is a painful type of arthritis. “High intake of animal proteins makes your urine more acidic and increases calcium and uric acid levels. This combination makes you more susceptible to kidney stones, while high uric acid can increase your risk for gout,” adds Yawitz.
Lemons are also keto-friendly, so go ahead and add a spritz of lemon juice to your ice water. One typical lemon wedge has about 0.5 g of net carbohydrates and only 0.2 g of sugar. The fruit also offers 3.7 mg of vitamin C, which is 6.2 percent of the DV. Lemon water contains antioxidants that fight free radicals, and it also promotes healthy digestion, according to the Cleveland Clinic.