Some people who start a low carb diet experience what’s called the “keto flu” or the “induction flu” in the first few days while the body is adapting to burning ketones instead of glucose. You can think of it as kind of a carbohydrate withdrawal.
The common symptoms are:
- upset stomach
- Lack of mental clarity (brain fog)
Many people have reported good results in minimizing these symptoms by doing the following.
- Drink plenty of water throughout the day
- Increase your electrolytes (sodium, magnesium, potassium). Initial weight loss in ketosis is mostly water, so the loss of retained water will also result in a loss of electrolytes. Adding more salt to your food can help, as well as magnesium and potassium supplements or by eating foods that are rich in these minerals. Another helpful approach is consuming salty chicken or beef broth during this period.
- Eat more fat — cheese, avocados, fatty meat, sour cream, coconut oil, olive oil, butter, heavy cream in coffee
- Minimize protein. The body can convert protein into glucose if you eat very much, and this can stall the transition into ketosis
I did not experience this in 2013 when I went on the ketogenic diet, but my 15 year old son had a couple of days in June where he felt crummy. This was about 3-4 days into the switch to removing carbs from his diet. It passed quickly and then he felt really good with a lot more energy.
In any case, do some research on this and decide for yourself how to prepare for the transition. You might even do a gradual reduction of carbs rather than diving in all at once.