Unfortunately, you may have been suffering from what’s known as the keto flu. When you first start burning fat instead of glucose, your body may experience flu-like symptoms: dizziness, fatigue, brain fog, irritability, and insomnia. This is a natural reaction and unfortunately one that you need to push through for a few days up to a few weeks. After that, many experience a huge increase in energy, which is one of the diet’s touted benefits. You can alleviate keto flu symptoms by keeping hydrated with electrolyte water, resting, gently exercising, and taking activated charcoal to bind any toxins that may have been stored in the fat you’re shedding.