I reluctantly post this as I related this story the other day in another forum on this same topic and it seems most bike folks are really sensitive about accuracy in these matters.
What I related over there somewhat tongue in cheek was I did a 25 mile ride with a friend last sat from the city to the country and the destination was an old farm converted to a brewery. I set my iPhone app to record the trip plugging in some guesses at my weight and the weight of the tour bike loaded down etc and mostly wanted to record the map and distance. When we got there I stopped the app and got a report that I had burned 2025 calories. I showed it to my friend and he said “Looks like you earned 4 beers!”
I didn’t know if it was remotely close or how he computed the equivalency beer factor so fast in his head but the number seemed about right to me. I was thinking maybe a better app would display directly in beers. Maybe an empty pint when you hit start and as you ride it fills up, each successive beer could be a little mug in the top that’s a counter.