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.
Since the 1970s psychologists have used mirrors to search for signs of self-awareness in both humans and animals. Along the way, they came to believe that humans were almost universally able to pass a mirror-based self-recognition test by 24 months of age.