The only time I didn't have problems keeping my weight down was when I cycled to work - roughly 10 miles, uphill and into the prevailing wind in the morning and easier back at night. In summer I'd often take a detour through a local range of hills for an additional couple of hours off road fun.

Was much faster than the bus and I didn't have a car at the time.

Now I have a 25 minute walk to work - but it's not the same.