Hello, Since you are diabetic, Pepsi cannot be recommended as it contains artificial sweeteners and high sugars. While the caffeine acts as a stimulant, increasing the activity of the colon muscles, the carbonation can cause bloating and gas, which might also prompt a bowel movement. You are advised to take high fiber in diet. Include food that help in better bowel movement like papayas, raw and ripe, prune and prune juice, coffee, oatmeal, lentils, etc. Keep yourself adequately hydrated, take water and fluids throughout the day, Dehydration triggers constipation. Do regular walking, do exercises. Sedentary lifestyle slows down bowel movement. Take laxatives. Suppositories are also helpful. Avoid taking food that is hard to digest. Avoid taking red meat, prefer to take lean meat to avoid constipation and difficult bowel movement. You should feel better in 1-2 days. If symptoms continue than you are advised to get clinically examined by a GP to rule out any structural problem that is causing constipation. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician