Trying ingesting Bragg's ACV (apple cider vinegar), the brand with the Mother on the label first thing in the morning. DO NOT USE REGULAR WHITE VINEGAR, MUST BE THIS BRAND. Add 1-2 tablespoons to 32 ounces of water and drink it first thing in the morning. You might find it unpleasant, but it gives a boost of energy. Plus you may be low on HCL (acid) in your stomach which will impact your digestion. ACV activates the HCL and it's a tremendous healer on many levels. Ifind it helps me acclimate better after fasting. When I don't take it, I notice the stomach rumbling, gas, etc.
Keep in mind if your stomach is rumbling, it's a definite signal that your body is not reading for that particular food or perhaps you have a food allergy . When the stomach purrs after eating, that's a good sign that it loves what you're eating. : D
You may also want to check out kombucha and other fermented foods to repopulate the good bacteria in your gut. Raw sauerkraut is a good one too. If you're particularly sensitive to digesting fats, complex carbs etc after fasting, you may want to consider getting a good vegan/vegetarian probiotic that comes in liquid or pill form which will do the same thing.