Well, what's your definition of "gaining weight over the winter?" 5 lbs? 10lbs? 10lbs+? I wouldn't kill yourself over 5 extra lbs (just due to the Xmas holidays) as long as you stay consistent on the bike and eat sensibly for the rest of the year. How many people can go thru life w/o eating a cookie!? IMO, most cannot, and certainly not me. For most of the population, it's not easy to maintain weight over the yrs as they age. Find a compelling reason to stay on the fitness program, and do your best to control/lessen the junk food intake and overeating.