>>76490574
Go get a kitchen scale, and put a cup onto it then zero it, then count how many sprays you need to register 1g.

For my oilve oil sprayer its 4 sprays for 1g which is like 10 (8.4) calories, so I know every 4 sprays that's ~10 calories, or I can count 2.5, 5, 7.5, 10, 12.5, 15, ... and so on as I spray.