When food enters the mouth it immediately starts to get broken down by the enzymes in the mouth such as lysozyme and the teeth. Once the pieces are small enough they then travel down the esophagus, working its way down to the stomach. The stomach is filled with acid (gastric juice) that continues to break the food down and acts like a holding tank for the food. The long process of completely breaking down the food to three categories, proteins turn into amino acids, fats get turned into fatty acid and complex sugars turn into simple sugar. The food does all of this in the duodenum which is located in the small intestine.

Anorexia is an eating disorder that causes an intense fear of gaining weight so the person will stop eating and drinking in order to achieve or maintain an unhealthy weight. Some of the complication include but are not limited to, Bone weakling due to lack of vitamin and nutrients from foods, Low white blood count that could lead to infection low potassium levels in the blood that may lead to irregular heart rhythms, malnutrition tooth decay espogus damage, thyroid problems, seizures due to loss of sodium, and fluids from loss through vomiting or diarrhea.

Bulimia is an extremely damaging disease to the digestive system. A person diagnosed with bulimia binge eats and then causes themselves to vomit up the food after the initial ingestions in order to not digest any of the calories. Stomach acid from the forced vomiting causes tooth decay and damage to the oesphgus .ulcers and ruptures in the stomach lining may occur from the repeated vomiting, dehydration can lead to kidney failure or damage.
References:

Scanlon, Valerie C. and Tina Sanders, Essentials of Anatomy and Physiology.-6th ed. Philadelphia: F.A Davis Co 2011

American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 5th ed. Arlington, VA: American