Leftover food comes to the rescue when you're too lazy to cook. But these are some foods you should avoid eating as leftovers. First, creamy pastas must not be eaten the following day as reheating is not an option, it may cause harmful bacteria to accumulate causing stomach troubles. Second, mushrooms contain proteins which must be consumed fresh once cut. If left over, especially at room temperature, mushrooms tend to become stale and unfit for consumption. Lastly, cooked eggs or egg-based dishes are the last thing you should think of eating as leftovers. Reheating eggs can lead to salmonella build up that can cause stomach infections.