Caffeine is a central nervous system stimulant, which can temporarily drive away drowsiness and restore energy. High-density black coffee chips containing caffeine can play a refreshing role when eaten in moderation. The mechanism of caffeine is to block adenosine receptors, thus promoting the release of neurotransmitters and increasing nerve excitability. In addition, caffeine is also considered to have the function of promoting fat burning. With the help of caffeine, exercise can improve the oxidative strength of fat.