I went on a 480 mile - 7 day (6 day riding) tour this year. My first of that length and duration and I thought I would lose weight also. When I got back, I had not lost anything (which really is a good thing since I ate and drank to maintain my weight), but what I did notice was that about a week or two later, I guess this ride kick started my metabolism cause I lost about 4 or 5 pounds and I was able to eat more and not gain weight?

Weird huh!