Sugar was available in boatloads in the 70's in Europe. Liters of soda and candy were consumed by kids, yet fat kids were a rarity. 'Normal' food didn't have all the hidden sugars, and was far less 'designed'. Also, meals were 3 a day, and 'sncking' frowned upon by parents. Another big difference was that kids and even adults naturally excersized all day, running, cycling, playing outside. The 80's made the streets unsafe to play do to the massive increase in car traffic, and those same cars made sure adults remained seated all day. The food industry had breakthrough successes in finding out ways to get people to eat more and more without reducing the hunger/craving, and started campaigning for 'snacking'. The resulting obesity crisis also needed to be social engineered so that people wouldn't stop overeating because of the unavoidable effects on body and health. So the fat-pride movement was nudged into existence, and even discussing the subject outside of the well controlled message of 'you don't get fat from eating' made taboo, while installing a victim culture externalizing all factors.

> Sugar was not readily available until relatively recently.

Fruit?

I'd put my money on a relation between abundance of food plus obesity because too high calorie intake is the main culprit of obesity.