Although no two Crohn's Disease sufferers are alike, there are some general guidelines to what you should be consuming.  You should have a high calorie, high protein diet.  Crohn's patients should also at the very least take a multi-vitamin.  This is all to ensure that your body is getting all the nutrients that it needs.  Remember, Crohn's Disease can cause your intestines to become inflamed, this will in turn make it hard to properly digest and absorb nutrients through the intestinal wall, and this will lead to malnutrition.  Other vitamin supplements or even injections, such as Vitamin B₁₂, may be needed as determined by your physician.  It is also very important that Crohn's Disease patients drink plenty of water to stay properly hydrated; water, like nutrients, are absorbed by the intestinal tract which may not work as efficiently when irritated.