Get ready for the keto flu
Most people already know about the keto flu, which can happen when you start the diet. It’s a result of the body adapting to the low-carb state. Lowering carb intake forces the body to burn ketones for energy instead of glucose. Once the body is in ketosis — burning fat instead of glucose — the keto diet is working. But you may not feel so great at first, hence the term keto flu.
Symptoms of the keto flu can include everything from headache, weakness, and irritability, to constipation, nausea, and vomiting.
“With the start of the keto diet, the body switches from using sugar as a source of energy to using the body’s stored fat,” Rahnama explained. “In the process of breaking down fat, the body produces ketones, which are then removed by the body through frequent and increased urination. This may lead to dehydration and flu-like symptoms, such as fatigue, dizziness, irritability, nausea, and muscle soreness.”
“With this frequent urination, there is also the inevitable loss of electrolytes, which can exacerbate these symptoms. In addition, as carbohydrates are a source of energy and stimulation, removal of this source of energy will result in increased sugar cravings, brain fog, [and] difficulty concentrating, much like most other withdrawal symptoms.”
For most people, the keto flu only lasts about a week.