Who does not like a big, juicy, delicious pizza? However, this is far from being a light meal and your digestive system would have a hard time processing it during the day: try to imagine how difficult it would be for your digestive organs to do that during the evening, when they should rest. Pizza is very greasy and it has ingredients that contain high levels of acidity, thus increasing the risk for heartburn.
You are what you eat, but did you know that you also dream what you eat? Not necessarily literally, but it is a known fact that fatty foods and sugary products (especially candy) have an impact on your brain waves and they can trigger nightmares. If you want a peaceful and relaxing night, then avoid junk food and opt for substitutes like oatmeal, which are lighter and contain less calories.