How long does it take for the body to enter ketosis on a water fast?

Just over 20 hours.Ketosis merely means that our bodies are using fat for energy.

Prepare yourself for the many side effects you may experience during fasting, like headaches, dizziness and nausea. Be prepared to stop the fast before any of these symptoms become overwhelming.

If you're stopping the fast don't eat large meals start with small ones, you're body will need to readopt.