I was born in the early 60s and from what I can remember portion sizes were much smaller. I don't remember feeling there wasn't enough though and yes, there was always bread with a meal. I suppose you get used to what you have.
If my mum went on a diet, it was bread, potatoes and puddings that she cut out. She was often on a diet, and my dad was too, but looking at photos now, they weren't massively overweight.
I think we graze and snack more now than we did when I was a child, particularly when out. I don't remember having big troughs of popcorn at the cinema, but you might get a (small!) choc ice as a treat.
I don't remember there ever being fizzy pop in the house, but I did have sweets (threepence rising to sixpence a week pocket money - pre-decimalisation). We didn't have chocolate or crisps in the house other than pocket-money stuff.
We had things like Instant Whip and Angel Delight (that may have been the 70s) but only ever after a meal and in small portions. We also didn't have a car and walked everywhere local.
I think that as a society we're more aware than we've ever been about nutrition, weight, fitness and health but we're also bombarded with easily-available, cheap foods that aren't good for us. It's a difficult one and I'm not sure we can easily go back to how things were.