I’m around 160lbs @ 5’9". FTP of 282.
I have a desk job but rest of time I’m pretty active, run to and from work 5 days a week which is 3.1 miles each way if I go direct but regularly tag on a extra mile or so if time permits on way to work. So although I am stuck at my desk most of day in addition to running, I go for a walk on a lunchtime to get my walking steps in. Regularly do ~18,000 steps a day (includes the running).
Do two weekend rides, one a tempo group ride with two free for all efforts up a climb and sprint finish ~2 hours long and then more social group ride of ~3 hours. Do midweek ride/trainerroad workout on a Wednesday.
Now I use a stryd running power meter and have power meter pedals on my bike so my calorie expenditure from running and cycling should be pretty accurate.
Last summer I cut down to 150 lbs used myfitnesspal to track food weighing it etc and got very lean etc but it felt quite severe at times. I want to reduce weight again as at minute I can pretty much eat what I want (within reason) and weight always hovers within a lb or two of 160.
This is where my question comes about if I know how much I have expended through exercise running or cycling because it is power based are those calories I should add to estimated calorie expenditure if I was just sat down all day? Or is it not as simple as that?