During acute symptoms, you should avoid raw vegetables and fruit, milk and dairy products and whole grain cereals. You may need to follow a clear liquid nutrition therapy or even nothing by mouth to give your GI tract a complete rest. (This may require hospitalization with IV’s with added vitamins and minerals, which can be achieved with total parenteral nutrition – TPN.) A clear liquid nutrition therapy is strained fruit or vegetable juices (apple juice, cranberry juice), broth (chicken or beef), plain gelatin, fruit ices, carbonated beverages, coffee, and tea. Besides Ensure, you can try Citrotein or Sustacal. That’s it.
When you no longer have acute symptoms, you can start a full liquid nutrition therapy by adding cream soups, cooked refined cereals, custard, tapioca or pudding, but milk products like yogurt, ice cream and pudding may still cause your symptoms due to lactose intolerance.
Crohn’s disease has symptoms similar to colitis but can occur anywhere along the GI tract. The cause for the symptoms is unknown. Various nutrient deficiencies can develop because of malabsorption during acute phases, which include diarrhea. Initially, loses of sodium, potassium, and water are of concern. Long-term symptoms can cause protein/calorie malnutrition along with deficiencies of Vitamins A, B 12, C, D, E and K, folic acid, calcium, iron, zinc, and magnesium. Oral vitamin supplements probably will not resolve these deficiencies during acute diarrhea phases. Weight loss and limited food intake during acute phases add to the decrease in your nutritional status.
I would suggest that when you are not experiencing symptoms that you should follow a nutrient-rich balanced eating plan including a daily multivitamin, with adequate fiber to maintain intestinal elimination. You will have to vary the fiber content of the foods you eat to find the level that works for you. If you are prone to GI obstructions, a high fiber nutrition therapy is not recommended. For persons without Crohn’s disease, 1 gram of fiber per 100 calories of food is recommended and would be a good fiber level to start.