If you are looking for an alternative to coffee to keep you awake at night, you should consider dark chocolate.
According to a study conducted by the British Medical Journal, dark chocolate has the ability to give an energy boost. In fact, it can boost your energy as much as coffee. Though dark chocolate might not have the same amount of caffeine as coffee, it has theobromines which improve your energy level and stimulate mental alertness.
Dark chocolate is also known to improve brain function and help the digestive system.