First of all, the stomach isn't really trying to "eat itself", although it feels like it. Also, your organs will not "shut down" or else you would die.
After your body realizes that making you miserable isn't working, it will begin to break down your muscle and fat stores for its protein and energy needs. At first your cells will use fatty acids and ketones as a source of energy and the liver will convert proteins and glycerol from fat into glucose for those cells that prefer it. After about a week most of the body, including the brain, will have shifted over to the use of ketone bodies as energy. Obviously the body goes into a much lower metabolic state to conserve energy, resulting in fewer bowel movements and an increased need for sleep/rest.
The liver will be hard at work attempting to create cholesterol, saturated fats and other nutrients that are normally derived from food. In fact many people experience very high cholesterol levels during starvation.
Upon reintroduction of food the body will begin to store as much fat as possible before it returns to its original metabolic state. This prepares it for the next time a starvation crisis arises.
Beavers without tails adapt by using their hind legs for balance, swimming with more effort, and relying on their teeth and body shape for survival.
Hypoxia, or low oxygen levels in the body, can lead to bradycardia, which is a slower than normal heart rate, because the heart tries to compensate for the lack of oxygen by slowing down to conserve energy and maintain proper blood flow to vital organs.
Yes, a body would not decompose on the moon due to the lack of atmosphere and extreme conditions such as low temperatures and lack of moisture.
Phyla such as Porifera (sponges) lack organs and have asymmetrical or no specific body symmetry. Another example is Placozoa, which also lack organs and have asymmetrical body shapes.
The study of food and its effects on the body is known as nutrition science. It involves understanding how nutrients in food interact with the body to support health and well-being.
There is no shortage
In an forlorn attempt to compensate for his lack of height Bobby wore shoes with six in heels.
Members of a highly mobile and diverse society compensate for the lack of accessible kin by diversifying and associating with people outside of their immediate family.
malnutrition
To compensate for their lack of personality and ungly faces
One of the main things your body will develop from the lack of citrus fruits alone would be scurvy. Have fun with that. Didn't your mother teach you anything about nutrition? Mine didn't.
Lack of food... The human body has 'autonomic reflexes' which shut the metabolism down when it needs to 're-charge'. Even if you're 'forcibly' kept awake, eventually the body simply 'insists' you get (usually a very deep) sleep for as long as the body needs.
Lack of food is more likely to lead to a quicker death than lack of sleep. While both are essential for survival, the human body can survive longer without sleep than without food. Prolonged lack of food can lead to severe malnutrition and organ failure, ultimately resulting in death.
Heartrate would increase due to an attempt to compensate for dehydration/lack of volume. Remember, the body always wants to maintain homeostasis.
Shock
Beavers without tails adapt by using their hind legs for balance, swimming with more effort, and relying on their teeth and body shape for survival.
Insulation and storing energy to prevent starvation during lack of food.