Renee:
I can totally relate. I lose in spurts too - in fact after the last 2 months of not losing anything, I was wondering if I even lost in spurts.
My theory...I think our bodies don't want to change. They get comfortable at the status quo and try to stay that way. This makes some sense because if we severely limit calories we might even gain weight. (I know I did.) We also have to up the time or intensity of our workouts because our fitness levels improve and our bodies become more efficient when exercising.
So if I take this theory further...it takes more calories to maintain weight at 300 lbs than it does at 200 lbs than it does at 125 lbs. So as we lose weight we should back off on the total amount of calories we consume...but we have to be careful not to go under that certain amount and put ourselves into starvation mode.
Also, fitness at 300 lbs is less than it is/was at 200 lbs is less than it is/was at 125 lbs. Hopefully along the way the muscle to fat ratio also improves so that our metabolisms are a bit higher. However, along the journey to our weight loss goal, we have to add more to our exercise plan to get as much out of it than we did when we first started.
For example - I have made time to walk 45 minutes each morning - and it is all the time I have to exercise. The route I took to walk for 45 minutes when I first started was about 1.8 miles. Now to spend the same amout of time walking my route is almost 2.8 miles. I anticipate that I will have to add more distance to the route soon to continue to walk the same amount of time and at some point I won't be physically able to walk any faster (and I don't want to run) and will have to find more time for my workout.
And then there's the age factor...losing weight was way easier for me 5 years ago. At age 40, my weight loss is 3x as slow as it was at 35. Five years ago (and before) my process of losing weight was to put myself in the "diet" mentality...suffer to get the weight off and then go back to "living". Now, I know that this has to be a lifestyle change in order to keep the weight off. That in itself is probably the most important part of getting through the plateaus. The scale may not be showing my improving health right now, but other factors are - my clothes fitting better, not feeling winded on the big hills on my walk, more overall energy, etc.
With 50 lbs gone - you should be really proud of your accomplishment. Keeping 50 lbs gone - even more proud of yourself. Now give yourself permission to do something different foodwise (like trying the South Beach philosophy instead of Atkins or WW instead of SB) for a few weeks or changing up your exercise routine. It may be just what your body needs to let go of those pounds its so comfortable with.
sorry this is so long...we're in this together.
-Laurie