Can anyone explain how negative calories work?

timpsmith

Hi there,

Can someone help me understand how negative calories work?

After a long bike, MFP deducts quite a number of calories. If it's to deduct "basal" calorie burn, I'm pretty sure Apple already accounts for that in their "Active Calorie" count.

Here's what I see in MFP vs Apple Fitness.

Any help is appreciated

Tim

Lietchi

I've read about syncing issues with Apple watches, wrong numbers being sent over to MFP.

Aside from that, the negative calorie adjustment is intended to correct your calorie burn when you haven't been as active as the activity level you chose in your profile. Sedentary is around 3500 steps, so it seems quite normal to me that you are getting a negative calorie adjustment with only 1100 steps. The exercise is irrelevant since the burn for that exercise is taken into account on both sides of the equation (Apple and MFP) and MFP's activity level is not intended to include exercise.

On top of that, it is possible the exercise creates a negative calorie adjustment if the number of calories burned during exercise is the gross calorie burn (including BMR): MFP compares total burn between MFP and Apple, so the 'extra' you got in your exercise calories gets subtracted through the calorie adjustement. It all adds up correctly in the end though, it just looks a bit funny. The longer your exercise session, the higher this number discrepancy will be (larger difference between gross and net calorie burn).

timpsmith

Lietchi, I think you're right — based on the activity level in my profile (active) I think probably MFP was anticipating a certain amount of activity already, even before cycling. It would be double-dipping, so to speak, if MFP were to merely sum anticipated activity + exercise activity. Thanks for chiming in and helping to clarifying this for me.