sleep and eat?

Well almost always, even if I eat a small meal, I feel sleepy after my mid-day meal. Also whenever I eat heavily, be it breakfast, lunch or dinner, I immediately feel sleepy afterwards! And yes, it's not healthy to sleep right after a meal also as you'll develop heartburn which is really painful! When you awake after a long nap after a heavy meal, you feel really drowsy and not refreshed at all!