Adafruit Ina219 mcu power consumption

Hello

Has anyone tried to use the Adafruit Ina219 to calculate the power consumption of an application running on the mcu ?

Welcome! The number one rule is to have fun with electronics. Adafruit is a reputable manufacturer that makes good products for the hobby market. There website not only gives you pricing etc but also technical information, a demo sketch plus more. Go to there website and try there demo software and see how you do.

The microcontroller or processor of a Arduino board runs always at full speed.
It does not matter what you do, it will use the same power.

Turning on leds, relays and motors make a difference of course. Some boards have Wifi, that needs a lot of power.
Sometimes a sleep-mode is used when a Arduino board is powered with a battery. Some boards have a floating point processor. The newer and more sophisticated a Arduino boards could show a (very small) difference in power consumption.