There are some signs which indicate that the body shifted to ketosis:
Liver creation of ketogenic bodies: your liver starts to transform fats into ketogenic bodies to be used as source of energy principally by the brain; your liver has as the same time to eliminate the toxins which where eventually contained in the melting body fats.
Short-Term Fatigue: initially, it is common to suffer from tiredness and low energy, also decreases in performance can occur. Since the body needs to becomes adapted to running on fat and ketones instead of sugar.
Constipation: a ketogenic diet generally involves a major change in the types of foods eaten and this can cause constipation mainly due to dehydration and salt loss.
Frequent urination: during ketogenesis the body uses the glucose stored in liver and muscles, this process releases water. As your carb intake and glycogen stores drop, your kidneys will start eliminate this excess water.
Bad Breath: this is caused by elevated ketone levels. Specifically, acetone is the responsible ketone for this, exiting the body though urine and breath.