Hi:
After more than 30 years I finally know something about this. Pretty much all of the pieces came together for me last year!
When you are cycling those calories it's preferable that you don't have a pattern. If you are eating the same amount of calories on Saturday and Sunday, from what I understand, your body figures this out. It's the same as some one who does the same cardio work out every other day and lifts weights every other day. We should be doing cardio and at least handweights for strength and mixing it up, the days AND the programs. Weekends try eating say, 1700 cals one day and 2000 on another, change the amounts each week and mix up all of the patterns every week; I think it's ok to repeat the same cycle for a month, meaning 4 different weekly patterns repeated monthly. Check out Freedieting.com. And yes, your body can build muscle quickly! Three years ago I started hand weights every other day (3 LBS later moved up to 8LB wts), just 10 miutes and 11 reps for 5 exercises: I had already lost about 30 pounds but wasn't getting the results I wanted. The first week I lost a total of 4 inches from my hips, waist and breasts and over the next two months I lost tremendous amounts some weeks, like 2 inches off my waist, etc-adding up to 10 inches a week! There were some weeks when I only lost a few inches total, and finally I got to the point where I sometimes lost just and inch or a little more and 3 weeks later I'd suddenly drop 3-4 inches.
I dropped rapidly from a 2X top to a well-fitting XL and sometimes a large medium Plus my pants went down 2 sizes!
I learned to trust the tape measure and NOT the scale. At the point where I was losing the most inches the scale sometimes registered no weight loss or just a pound a week, etc. And this is because muscle truly weighs more than fat! There are size 4 and 6 lady bodybuilders out there who are under 5'5" and weigh in the 150s!
Don't get discouraged. I would probably be at my goal if I wouldn't haven't gotten a case of the "not fast enoughs" and had a lot of outside stress. When those inches were dropping off, even though my weight loss "slowed" (due to the muscle weighing more)
my doctor kept asking me what I was doing; my BP was at 121/70 when I been having trouble staying below 135/80 on my medication; my cholesteral was normal, my blood sugar was better than usual. Oh and I try to stay away from too many processed carbs; I don't know what your plan is...Best wishes