The effect of drinking coffee on blood sugar varies from person to person. The effect of coffee on blood sugar is generally small for normal people, because insulin is secreted on demand in normal people, and insulin is secreted when drinking coffee or eating, thus maintaining blood sugar in a relatively constant state, usually 3.9-6.1mmol/L in fasting state and <7.8mmol/L 2 hours after meal, so normal people drink coffee appropriately, which generally does not affect blood sugar. And patients with diabetes or abnormal glucose tolerance are generally not recommended to drink coffee, because coffee is high in calories and has a greater impact on blood sugar, which is not conducive to fasting blood sugar control. If you want to drink it very much, you can drink some hand-ground coffee or sugar-free black coffee in small amounts while not adding sugar, milk or coffee mate, which is low in calories and will not cause excessive blood sugar fluctuations. It is not recommended to choose high sugar and high fat coffee, the taste is sweet but it will affect the stability of blood sugar. It should also be noted that both normal people, and patients with diabetes or abnormal glucose tolerance, try not to drink strong coffee at night, because the caffeine in strong coffee can stimulate the central nervous system and make people excited, which can cause sleep disorders. In addition, too much coffee can lead to calcium loss and osteoporosis.