Velveteen, don't just lurk - feel free to post too. You don't have to be at goal to post here. Besides, you're a recovering maintainer and belong here anyway, so please don't be a stranger.
Just like Helen, I know for certain that I couldn't have lost the weight without exercise and absolutely wouldn't be able to keep it off without exercise. The funny thing is that I was convinced for 46 years that I despised exercise. And now I'm a personal trainer? The world works in bizarre ways!!
I was 46 when I lost the weight and am 52 now, post-menopausal, and hypothyroid. Talk about three strikes against weight loss and maintenance! I'm absolutely convinced that there isn't any way to keep my calories low enought to keep the weight off without daily exercise. Otherwise I'd seriously have to be eating under 1000 calories per day and that just isn't going to happen.
Plus I agree with Paperclippy that exercise has a big mental component. It forced me to look in the mirror and become aware of how my body moved, looked, and felt. After ignoring everything below my neck for twenty years, exercise integrated my mind and body back together and made me a whole person. And wow, the mental aspect of being strong! It's (dare I say it?) empowering.
Exercise has paid off big-time for my health. My various test numbers are out-of-this-world good and my doctor has told me that only exercise can get someone to where I am (my HDLs are twice as high as my LDLs). I have severe arthritis in my knees and back (thanks to 20 years of weighing more than 200 pounds) but my doctor says I'm the fittest and most flexible patient he's ever had. And the muscles I've built are protecting my joints and preventing more pain. So even though I'm paying the price for years of obesity, exercise is keeping me going.
I'm currently trying to lose five pounds so I'm in all-out weight loss mode with my exercise. I do an hour of cardio every day, mostly on the elliptical, at a fairly high intensity. I lift weights on a five day split (back, chest, arms, legs, and shoulders) and do an extra day of shoulder rehab exercises. And to try to strengthen my lower back, I do 15 minutes of core exercises a day. Good thing I'm an early morning person because I can get most of it done before breakfast and then pop back into the gym in the afternoon for a quick cardio session.