Coffee is generally recommended to be best drunk during the day, especially in the morning, after lunch break and 30 minutes before exercise for best results. 1. Coffee contains caffeine, which helps to refresh, improve mental state and keep the mind awake. Drinking coffee in the morning helps to keep the spirit of the day in a better state. 2. Most people have to cope with the afternoon’s work after the lunch break, so drinking a cup of coffee after the lunch break helps to relieve the fatigue after the lunch break, and more energy to put into the work. 3. Drinking a cup of coffee before exercise can enhance the mental state, improve the efficiency of exercise and help the body to consume more calories. But pregnant women, osteoporosis, renal failure, coronary heart disease and other people are not recommended to drink coffee, so as not to cause discomfort. In addition, caffeine is easy to excite the nerves, stimulate gastrointestinal motility, it is not recommended to drink coffee on an empty stomach, so as not to cause bloating, diarrhea.