A while ago (ummm, 3 or 4 years) I visited a customer in the city, afterwards I walked back to where I had parked. I had to walk up a steep hill for the length of 1 city block and when I got to the top I thought I would die. I hadn't turned 40 yet and I couldn't walk up a hill without being totally out of breath and feeling like shit! I felt that if things continued like that then I could look forward to some serious health problem (type 2 diabetes or whatever) so I needed to fix me.
I started walking daily for 30 minutes, then within a couple of weeks I decided to stretch it to a full hour. I walked almost every day for a full hour covering about 6kms (~4 miles) and after a few months I had moved my belt in by 2 notches. My daily walk incorporates 2 steep uphills and I work up a good sweat, but I don't feel like I am going to die when I get to the top of the hill. I can climb stairs and hills without a problem - I think that is as it should be!
I could still lose some weight, but overall my health is OK. I don't walk every day now, but I still cover 6km in 1 hour about 4 or 5 times a week. I didn't do it for anyone else - this effort I put in is purely for me.
I have also made changes in my diet now and then:
I cut out fizzy drinks quit a few years ago and now nine tenths of what I drink is chilled water.
I cut out white bread a few years ago, wholegrain/multigrain bread has just as many calories but has more fibre and nutrients.
I stopped using my deep fryer about 3 years ago and I don't miss it at all.