Does Black Americano Coffee Affect Blood Sugar? CGM Tested

Ever wondered how a simple black Americano affects blood sugar? I tested it with my CGM to find out. I drank 150 ml of plain Americano — no milk, no sugar, just black coffee. My glucose started at 5.7 mmol/L and rose slightly to 6.1 mmol/L after 30 minutes — just a 7% increase. That’s well below the 30% spike threshold recommended by health experts. This small bump could be due to cortisol, the “wake-up” hormone, rather than any actual sugar response. Bottom line: your morning Americano is blood sugar-friendly..

Metabolic Health Insights 🔬

Black coffee, including Americano, is a low-glycemic beverage with zero carbs, making it ideal for those aiming to stabilize postprandial glucose levels and support insulin sensitivity. This test shows it causes only a minimal glucose response, likely influenced more by hormonal factors like cortisol than by nutritional content. For individuals with insulin resistance or metabolic goals, unsweetened black coffee can be a great daily beverage. As always, the key is to avoid adding sugar or high-carb creamers, which can turn this metabolic win into a glucose spike.