I must have been a rarity as we had two cars in the late 70s - my mum drove, which I think was a rarity in itself - and my father had a company car. Before that I think we had just the one. I walked to primary school but we moved house in 1979 and it was further to walk from the new house - I think most of the time my mum dropped me off and collected me, so I wasn't walking much. I also wasn't at all sporty. I did go out on my bike a lot though.
I don't think food was healthier though, there were definitely trips to tuck shops etc and every Saturday I used to buy myself 10p worth of cola cubes or something similar (it may have been the very early 80s by then). Also the chocolate bars were much bigger, eg Yorkie bars which are a shadow of their former selves. I always had a school dinner though, for better or worse, it was meat and two veg and sometimes ok, sometimes disgusting. Then the catering staff went on strike and we had to take packed lunches (and I did have crisps and a small chocolate bar every day eg a Breakaway or similar). When they stopped striking, some people never went back to school dinners.
We always had brown bread at home - and juice rather than squash. But fizzy drinks were only for Christmas. We used to have fish and chips for lunch every Saturday and occasionally went to a local pub for chicken and chips in a basket. I think the all-year-round availability of food these days has made it all less of a treat, although Brexit could change that if supply chains dry up - we may well find we have less choice (as is the case in Switzerland - plenty of food, don't get me wrong, but they don't have the choice of brands).
We moved house about every 4 years. In terms of heating, I can't remember what we had in the first house I remember living in but we had electric wall heaters in the second house and the third house was pushing hot air through vents in the floor, my dad ripped that all out and put in storage heaters. The first house I lived in which had gas CH was from 1988.