Why Your Tummy Hurts If You Eat Too Much Watermelon Some people experience discomfort or pain in the stomach after eating watermelon. Watermelon is a natural fecal matter softener. It works to break up old, hardened waste that can sit in the intestinal tract like clay over time. As this waste begins to dislodge, you might experience bloating or cramping until your body clears it out. This is why it’s best to eat smaller amounts of watermelon at a time if you do sometimes have pain or discomfort