Black coffee contains high caffeine, which does not add sugar or milk, the taste is relatively bitter, can play a refreshing and fatigue, usually recommended to drink after lunch or in the afternoon is better. Black coffee contains caffeine, which can promote the digestion and decomposition of fat after meals, and after lunch the body is prone to sleepiness, at this time choose to drink a cup of black coffee can make the body maintain full of energy to put into the afternoon work. A cup of black coffee in the afternoon can keep the mind awake while increasing the sense of satiety, to relieve the state of hunger in the afternoon work. At the same time, the caffeine in black coffee has a stimulating effect on the heart and nerves, has a certain diuretic, blood circulation and other effects, for hyperlipidemia, dizziness, headaches have a certain improvement effect. But too much caffeine intake on the human body has certain disadvantages, easy to over-stimulate nerve excitement, leading to tachycardia and insomnia, so it is recommended that the daily intake of about 200ml, and do not drink before bed.