Make guesstimates for timeline item calorie consumption values

[sobri909]

This is the second most often requested feature for Arc App, after the Moves data importer.

I was just about to add it to the tasks list in the Arc App private repo when I realised there's no reason why it can't be done in LocoKit directly.

This also relates to #24. That task is for importing this data from HealthKit. Possibly the same TimelineItem property (item.activeEnergyBurned) should be used for this one. Although I suspect it might make sense to store it in a separate property and database field, so that it can be distinguished from more accurate calorie burn data sourced from wearable devices.

Misc Notes

• "Mifflin St Jeor Equation"
• https://en.wikipedia.org/wiki/Basal_metabolic_rate
• https://sites.google.com/site/compendiumofphysicalactivities/

[bionicl]

I've done some basic digging around active burned calories values and I'll share my knowledge if that would speed up your process a bit.

Here is a MIT table I've found: https://www.topendsports.com/weight-loss/energy-met.htm
And here is the equation:

burned cal = activity multiplayer ✕ time (minutes/60) ✕ average speed (km/h) ✕ weight (in kg)

Activity multiplayer is based on above link, and after some math and comparing to Moves results, here are the values:
Walking: 0.79
Cycling: 0.37
Running: 1.03

Example of 30 minute walk for 6km/h:

0.79 ✕ 0.5 ✕ 6 ✕ 80 = 189kcal

As I said, this values return almost the same results as the Moves app, but that of course doesn't mean that moves app returns correct values 🤔

Hope that'll help, good luck with development!

[sobri909]

Great! Thanks 😄