Well, I tried on a few things that I was thinking of purging from the depths of my closet, and they're a bit snug, so that is my cue that my weight is up and I need to dial back the eating.
The issue is certainly not my activity level. I've been walking/running almost every day that I'm not biking. And yesterday I did my longest training ride yet -- 80 miles -- in preparation for my century ride in two weeks. Oddly enough, I felt stronger finishing the 80 than I did the 70 mile ride two weeks ago, but it was much cooler and less humid yesterday.
So, this morning I'm finishing off my leftover pancakes from this weekend (I can't let them go to waste! ;-)), and then I'm watching the food intake more carefully for a while.