Hi welcome - Instant or quick weight loss not all recomended. so ,low blood sugar or sugar fall may be a chance. hence , few symptoms are common..like hypoglycemia, excessive thirst, unwanted weight loss, Even it can effect liver, heart, kidney all. a lot of nerveous systems disorders may be seen

Hi, keto diet has to be followed under strict supervision only.  There are a few side effects involved like irregular heartbeats, hypoglycaemia, fatigue, shaking, chills etc. It's like any other diet or activity routine once your are off this them you may weight on weight. So yes you need to follow a maintenance diet post ketogenic diet.