Summarize:

If your body is properly hydrated, you're less likely to become constipated and develop fissures as a result. You should be drink at least 2 US quarts (2,000ml) (8 cups) of water each day. You can drink more than that, if you like. Fiber and leafy greens will help keep your digestive system healthy, which in turn prevents hard stools. This can help prevent fissures. Good sources of fiber include whole fruits, vegetables, and beans. Eat leafy greens such as spinach, kale, and cabbage. Delaying a bowel movement can cause constipation or make it harder for you to go later. That in turn can cause fissures. So as soon as you feel the urge to go coming on, go! Because constipation can cause fissures, taking foods out of your diet that can cause constipation can help prevent fissures. Cut out cheese and other dairy products, chocolate, and fried foods. It can also help to cut back on red meat. Getting 30 minutes of exercise in each day can help prevent fissures. Regular physical activity promotes regular bowel movements, which can prevent fissures.
Drink more water. Incorporate more fiber and leafy greens in your diet. Don't delay going to the bathroom when you feel the urge. Avoid foods that cause constipation. Exercise regularly.