I worry about losing weight in only three weeks and still remaining strong. From what I read, I don't think you can really lose much in that amount of time--it will be mostly water. Although I don't use it that much, I really appreciate the "granny gear" on big hills. I did a 5 mile straight up hill yesterday and blessed it! It is easier on the knees and legs; if you blow out a knee in the midst of a multiday ride it could be absolutely miserable if not fatal to the rest of the ride.