I am sure some one else willadd on to my 2cents! but here goes.
Hunger is not only physical there is a mental component as well. So let's say you are a regular 3 meal a day type eater initially your body is responding to the programming that oh I am about to eat. Your digestive juices are starting to flow those cells which are used to food at a certain time are starting to chant "We Want Food!" Your mind begins to wonder hmmm what will I eat and if you are late on your schedule ... what ever it is you feel like you are starving both mentally and physically.
So you must get beyond the mental programming of food that also gets those digestive juices flowing. That what can take time and that depend on you and your readiness to fast as well as your preparation to deal with the mental "need for chewing" or your own personal food isues if any.
Your body will go into rest once th food consumed has moved through the digestive tract which equals Mouth throat esophagus stomach small intestines large intestines rectum toilet
The stomach is at rest as long as there is nothing that requires it to churn itself with juices to break down. The intestines however are where your nutrients are absorbed and wastes filtered into via the lymphatic system so they never truly rest. If they ever stopped working which happens to people who take no food or liquid by mouth for an extended time like those in a coma or those who have had abdominal surgery your body would reject any and everything including water. You would throw it up. I have seen this in the hospital. So rest is relative. Your gas should decrease, the amount of intestinal churning and bowel movements may decrease because bulk activates unless you aid it with enemas and laxatives - You may still have bms but not so regular or as hard