I used to use the garmin 705 calories burned as my basis for tracking calories in calories out, that was until I got a power meeter. I now use the kilojules as a 1:1 ratio for calories burned and I'll tell you, the garmin is about 1000 calories high as are the calculators online. If I am feeling strong and there are no downhills, I'll generate 800 + kilojules an hour while riding.