MFP calories expenditure figures can be so off.

saintor1 wrote: »

Since the beginning of this year, I added cross-country skiing to my daily routine. For a moderate effort (in sweat) and my weight, MFP estimates 705 kcal per hour. I noticed that my weight loss pattern has changed in the last 2 weeks.

Looking at other calculators, MFP is the highest of all by almost 200 kcal. Moral of the story, for calculating exercise, I no longer rely on MFP!

If you just added XC skiing in the last couple of weeks, on top of whatever you were doing before, keep in mind that you'd expect to see some extra water retention in your scale weight for a while.

I'm not arguing that MFP's estimate for XC skiing is accurate. Even theoretically, it's a gross estimate when you want a net estimate, so at least backing out estimated BMR/RMR calories would be a good idea.

Beyond that, I don't know anything about you, so I don't know your fitness or energy levels, so don't take this next as any kind of accusation. I have no way of knowing if your "moderate" is their "moderate" (are you going 4-5 or 5-8mph, for starters - that's likely more meaningful than sweat or perceived exertion, in this case).

I don't know for sure (too lazy to look it up), but I suspect the METS research for XC skiing was done on fairly skilled skiers. Most of the people I see XC skiing, when I go out, are not working very hard. They're mostly kind of shuffling along, maybe a little glide in there, and they look comfy all bundled up in down coats and such. They're not burning anything remotely close to 705 calories/hour. The rare serious, skilled skiers are flying, and lightly dressed because they're working hard enough to be warm from the inside out.

I haven't skied yet this Winter, but the 4-5mph version, for me, would be 435 calories/hour, which doesn't seem that crazy, to me, compared to well-powered-metered other exercise, especially after I do the gross-to-net conversion by backing out estimated BMR. Since I walk around 4mph when I'm going for it, I'm pretty sure I can ski at that speed.

If you care, you can usually figure out the nature of the METS research for any given activity. It's a research-based method, so not wildly nutty, though I do think it's more useful for some exercises than others (because of the nature of the activity truly varying in calorie expenditure based on body weight, or imprecision of intensity benchmarks, or limitations of the specific study, or . . . .). (More info here: https://sites.google.com/site/compendiumofphysicalactivities/home)

For sure, BMR/RMR should be backed out, but that's usually mostly arithmetically meaningful in the big picture only for longer, low-intensity exercise.