When a patient opts for stomach bypass surgery in order to lose weight, their stomach is reduced in size and reconnected to their small intestine.  This procedure facilitates fast weight loss because the newly reconfigured stomach helps the patient to feel fuller more quickly after eating a small meal in addition to physically not being able to eat large amounts of calories. Stomach bypass surgery, which reduces the stomach's volume from 32 ounces to roughly one ounce, can only be successful as a weight loss tool if the patient follows stomach bypass surgery diet guidelines outlined by their physician or nutritionist.

The stomach bypass surgery diet represents a new way of eating for the patient, one that focuses on consuming foods that are high in protein, yet low in calories, fat, sugar and fiber. Immediately following surgery, the recommended dietary choices highlight proteins such as red meat, pork and chicken or turkey served without the skin.  Protein consumption right after surgery is very important since protein helps the muscles of the body heal. Seafood, eggs and cottage cheese, all healthy food choices high in protein and low in fat, are also recommended on the stomach bypass surgery diet.

Foods containing sugar are restricted on the stomach bypass surgery diet because they represent empty calories for the body while healing, they are high in fat and counteract the objective to loose weight, in addition to triggering dumping syndrome after surgery, causing uncomfortable cramping and nausea in most patients.

High fat and fried foods are eliminated from the menu using the stomach bypass surgery diet because fats are difficult for the body to process once the stomach has been greatly reduced in size. Too much fat can cause such adverse reactions as heartburn, diarrhea and nausea in stomach bypass patients.

Foods high in fiber are eliminated from the patient's menus following stomach bypass surgery because the shrunken stomach no longer can handle such bulky foods and the amount of stomach acid to digest them is also curtailed due to the new size of the stomach.

Because the amount of food allowed is very small and the variety of foods allowed on the stomach bypass surgery diet is quite limited, it is essential that stomach bypass patients supplement their diets with an assortment of daily vitamins and minerals as recommended by a nutritionist. The core of these include Vitamin B-12, calcium, iron and folate, all of which can become deficient in a stomach bypass patient's body rather quickly while on the stomach bypass sugery diet.

It is also essential that stomach bypass patients drink enough water throughout the day while observing the guidelines of the stomach bypass surgery diet in order to keep the body well hydrated.