I was in a three-week slump (I wouldn't call it a plateau, as it wasn't long enough to be one) and couldn't figure out why. My husband suggested that I change up my exercise routine. I flew off the handle a little: "Great, so you don't think I'm pushing myself sufficiently? Hmmph!" But I thought about it a little more and realized that I wasn't really giving my all to physical activity.
It's been a week and I've had to tell him that he was completely right (I'm actually glad to tell him that in this case, though). Instead of five days a week of walking a set 1-mile route or half an hour of stationary biking if the weather was nasty plus lifting a couple of times a week, I increased my walk distance and speed. I added cycling to walk days and lifting to non-walk days. I went to heavier weights. I added intervals of rapid cycling to my sustainable pace and upped my efforts there.
I'm not actually spending more minutes per day exercising, I'm just intensifying what's already there. You may already be giving it your all, but I admit I was half-***ing it sometimes, so just going at stuff full-force was enough to start me out of my slump.
You've lost such an incredible amount already that your body might just be pausing for a little bit, kind of like a mountain climber might rest on a ledge and gather her strength for the next push. Maybe you just need a little change-up with your workouts to prod yourself up the mountain--especially since you're already so very close to the summit.
