>> The official line has been that saturated fat causes heart disease, and that replacing fat in packaged goods with sugar was ok. This is why we have candy in the United States proudly labeling itself as a “fat free food”, and we used to have marketing campaigns touting the weight loss benefit of sugar.

Did US public health organisations actually recommend replacing fat with sugars? I find this very surprising, if it is the case. I wouldn't be surprised if that was instead a practice adopted by industry, despite and against official recommendations.

For example, Wikipedia tells me that diet Coke was first sold in 1982. That must mean that there was, already, a clear awareness of the detrimental effect of sugar, and sugary drinks in particular, on health. That awareness can't have come from the soft drinks industry itself so it must have come from public health officials.