"the diet industry has a lot to answer for in that sense too -"
Definitely.
It almost doesn't matter what is in a food, it can't be good that people are being pushed to eat all the time.
Some children could eat chips 5 times a week (judging by my friends in the 70s) and be almost painfully skinny. but maybe they didn't eat between meals. Maybe cereal bars, packaged dairy things like tube yoghurts and cheese strings, etc didn't exist.
On the other hand, nobody seemed remotely scared of biscuits. They were around.
But things weren't pushed in the way they are now. There is an enormous industry trying to make every second a snack-portunity.
I have always worried about my weight and I am perhaps a bit more attuned to this but when I had children I was astonished at the alacrity with which the apparently intelligent (but naturally slim, so less cynical perhaps) women who had children with me, grabbed all that packaged stuff which starts being marketed the second your baby is 4 months. No salt, only natural sugars (whatever that means) nut free, blah blah blah, hordes of women with Orla Keily bags rustling with packaged saltless junk carbs.... everyone, nearly everyone, seems to go for it.
People stuff carbs into small children in church now! I was astonished when I saw this.
Anyway I think that excessive focusing on food (even in the name of health) = selling food = pushing more eating, pushing at times when our forebears wouldn't have considered it. Relative to this I don't see fatty bacon (for dinner or breakfast) as a problem (for instance - apart from anything else, someone has to cook it, so it is a considered occasion of eating, not a lazy habit) - so the kneejerk push to low-fat really bothers me
Also, don't forget everyone used to smoke. Do we want to use that as an appetite suppressant? No one talks about that when they talk about trends and statistics