Coke zero (1 piece)

Try caffeine-free Coke Zero or plain sparkling water; caffeine can raise glucose in some people through stress-hormone effects.

Avoid drinking Coke Zero on an empty stomach, when sleep-deprived, or during acute stress, and compare readings under more consistent conditions.

Have it with a protein- and fiber-containing option such as eggs, plain Greek yogurt, almonds, or non-starchy vegetables rather than alongside carbohydrate-heavy foods.

Take a 10–20 minute easy walk after drinking it, if safe for you; light activity can reduce post-drink glucose elevations.

Repeat the experiment on separate days and check that your sensor is not affected by pressure, timing lag, or normal measurement variability.

If the rise is repeatable or substantial, discuss it with your clinician, especially if you use diabetes medications or have symptoms.