I think I've been entertained by reading the last three pages, but I've definitely had enough now. So I'd like, if I may, to put in my two cents re the original question...
Motivation is indeed hard to find in the winter months sometimes. I commute all year round, so going to work is my motivation in the week - I have to do it.
However, regarding "leisure" riding, agreed - this is very easy NOT to do. I don't have so much trouble with getting out cycling myself, but for running I have to make it feel like something easy:
There are some woods near where I live. They aren't very big. It takes me 7 minutes to run round them once.
So if I know I "should" go for a run, but really don't fancy it, I put my gear on and say to myself "I'm just going to do 1 lap". After all, it's only 10 minutes out of my day (once I've run to the entrance of the woods). Psychologically I find this much easier to do than set myself the target of running for 40 minutes or whatever, which I can easily say "Oh maybe I'll do it tomorrow instead" to.
Invariably, by the time I've got to the end of that lap, I'm warmed up and feeling a bit more energised and I'll go "I'll just do 1 more". By the end of lap 2, I'm beginning to get into the zone, and can then add 2,3,4,5 laps - whatever I have time and inclination for. I always end up enjoying it, and always glad that I got my a*se in gear and did it.
If you're finding trouble getting motivated to get out the door, do the same thing. Gear up, and literally tell yourself "I'm just going to ride 3 miles". I don't know your pace, but lets assume that's not going to be more than 15 minutes for you. I bet you'll get to the end of that 3 miles, and feel you can carry on. Do it in laps if you like - means you've always got the "get-out" of stopping at the end of the next one but hopefully you'll find that you'll get there and actually want to keep riding for "just one more".
The other thing you could do is ride with someone. Riding with company often makes the miles go quicker somehow.
Once you've got back into your cycling, hopefully the desire to just eat junk all the time will resolve itself a bit as you'll feel fitter and more energised generally. And with this, you'll start to lose the weight again.
Finally, no matter how seasoned-a cyclist you are, the first ride or two back after a break are ALWAYS harder than they were when you stopped, and harder still when the weather is cold and the days are short. It will get easier again very quickly - this I guarantee!