That's an interesting study, Eden! But I'd venture the idea that exercising for longer periods of time in cold weather is slightly different. 45 min isn't very long, and for the record, 20 deg C is considered excellent bathing temperature over here...

But the study makes sense anyway. In cold climates, carrying a little extra fat is probably what evolution considers a really good idea. So maybe the stimulated appetite is to get you to eat a bit more and add a little insulation, so that you can survive the cold for longer. It would be interesting to see if people carrying extra body fat in the first place had the same appetite hike or if it plateaus once you better equipped to manage the cold.

I've done some longer skiing trips in cold weather, and I especially craved fatty foods after a day or two, not sugar.