6 to 8 hrs for digestion. it stays in the stomach for 2 hours and then in the intestine for another 2 hours. the undigested food goes to the large intestine and the digested food goes to whole body through blood. Carbhydrates and proteins about 1 1/2 -2 hrs. Fats 2 hrs.
And based on that a foetus does not posses self-awareness. Human babies have been found to become self aware between the ages of 18-24 months. The rouge test is a self-recognition test that identifies a human child's ability to recognize a reflection in a mirror as his or her own.
Everybody thinks they know themselves when, in actual fact, they do not. Therefore, it is necessary to reach the full knowledge of oneself. This can be done with incessant self-observation. We need to see ourselves as we really are.