20g black coffee powder should be mixed with 120g water. Black coffee contains 42 calories per 100g. Black coffee contains caffeine, which can stimulate the nerve center, make the mind clear, maintain abundant thinking power, concentrate and improve work efficiency.

Caffeine can also make muscles contract freely, improve exercise ability, and have the functions of strengthening waist and knees and strengthening bones and muscles.

Caffeine can stimulate gastrointestinal secretion of digestive juice, promote intestinal peristalsis, help human digestion, prevent gastroptosis, and has a good effect of invigorating stomach and promoting digestion.