At that time, medical opinion believed that it was the ingestion of fat, as opposed to mere calories, which gave us heart disease. Consequently, those trying to eat healthily were often bamboozled into buying low fat foods, while not realising that 'low fat' didn't necessarily mean 'low calories'.
Hence the epidemic of obesity: the public aren't truly aware of what they are eating, even though by law it is written on the packet.
All this points to one important conclusion: you can blind people with science (or, more strictly, make them obese). There's too much information, it's usually printed in tiny type, and often the really important bits aren't easy to appreciate.
Sure, there's the calorific content (per 100 grams) - but the pack in your hand doesn't necessarily contain 100 grams, so you may have to do some awkward mental arithmetic. And just to confuse things further, the energy content is stated both in kilojoules and calories.
Yes, there's a traffic light system - informative, but I suspect too complex for most people. Don't forget: the best is often the enemy of the good. All the facts are there - but often large amounts of complex data can hide important information.
A simple suggestion
So I have a simple suggestion to help everyone deal with obesity: make it an additional legal requirement to print the calorie content of the total pack, and of the serving, in VERY LARGE BOLD TYPE on all prepared or packaged foods.
Most importantly, this should apply to all drinks, both alcoholic and non-alcoholic, many of which have a colossal calorie content.
Similarly, all food outlets should display the approximate calorific content of each item (as some restaurants now do voluntarily).
Doing this would make it far easier for the average non-scientific person to count the calories in their meals - and to understand at long last that a food labelled 'low fat' may actually be stuffed with calories.