The hills are a lot easier if you dont have to pull a lot of weight. Apart from your own weight, you can save a lot by keeping a lot of stuff at work - towel, shoes, lock, pants, shampoo etc. If you regularly ride to several places, keep a lock at each - several keys are a lot lighter than a decent lock. I carry a light lock on my bike incase I have to make a quick stop on the way. Also it is easier if the weight is on a rack on the back of the bike, rather than on your back. After the climbs, I find I get a quicker recovery if I keep pedaling at a low effort on the downhills. The cycling hasnt done anything for my weight over the past 37 years but it has made life a lot more enjoyable.