How Black Decaf Coffee Affects Blood Sugar (CGM Tested)

Is black decaf coffee safe for blood sugar? I ran a CGM test to find out. I drank a plain cup — no milk, no sugar, just black decaf. My glucose started at 5.5 mmol/L and rose only slightly to 5.7 mmol/L an hour later, a tiny 4% increase. That’s well within healthy limits, confirming this drink doesn’t trigger a glucose spike. It’s a great option for anyone looking to enjoy a comforting beverage without messing with their blood sugar. Just remember: adding sugar or milk can change the outcome significantly.

Metabolic Health Insights 🔬

Black decaf coffee, free from carbs and calories, has minimal impact on postprandial glucose levels. This makes it an excellent choice for those working to maintain stable glucose, improve insulin sensitivity, or manage metabolic health. While caffeine can influence glucose differently depending on individual tolerance and dosage, decaffeinated versions remove that variable. When used mindfully — without added sugars or high-glycemic creamers — black coffee supports glucose stability and metabolic flexibility. CGM testing proves it’s a smart beverage for a low-glycemic lifestyle.