Personally, Pen, I can't add weight to any "normal weight" as I don't have one. I have a goal bodyfat and weight combo, and perpetually strive for it. I still lose like 10 pounds a week if I get really bad, and 40 or so in 3 months time, etc...and it takes forever to gain any of it back in the right way, I've done it 3 times now.
As for the winter, I lose weight in the winter because that's usually my "bad season" and I've rarely been able to work out. I was 147 in 2007/08's winter, and about 160 last 2 years. Now I'm up around 200ish. Being an exception is frustrating. If I lose fat on purpose, they automatically chalk it up to a bad flareup. If I gain muscle, they assume I'm "all better" when I still go 15+ times a day.
Btw, it's "Tony Little" but I suppose you can mock him and call him little Tony. lol
I'd also like to add for the weight loss advice to find a sport you enjoy, especially one you can do solo, like basketball (mine)...swimming, biking, soccer, boxing, football ("American")...and it won't seem like a chore. The time passes quicker and you're more likely to do it when "scheduled".