If science could take 10 minutes and finally confirm that junk food is causing single nucleotide polymorphisms in the FTO gene and as a result appetite suppression/acyl-ghrelin hormone production goes out of whack, we could turn it around to old levels. Not for the currently affected, but for the next generations.
I don't really think the science is the problem, if you look at WHO - when they published their guidelines for reducing sugar to less than 10% of daily intake, that advice was based on legit scientific studies, but it got suppressed multiple times, by paid-off government officials and sympathetic funding bodies - even after it was finally published, literally none of the official health bodies are changing their policies and advice to reflect it. In the United States - it seems to have become the norm to feed children high-calorie toxic food until they get ill, then the solution is to send them for bariatric surgery, rather than force the food companies targeting them, to behave.
I also think that most people don't need a scientist or a study to tell them that eating a mars bar, or a big-mac every day is bad for them. In my opinion the problem is these foods are specifically engineered to taste great, and aggressively pushed out to make money. In the final analysis, literally most of the food in your average supermarket is bad for you, resulting in chronic metabolic disease and the levels of obesity present today.
I think there has to be some form of legislation, because some of these companies are taking the **** for example, take these things, which are targeted at children;
It claims basically to be fruit, with 'no added nonsense' (no added sugar) which is true, as far as the legal standpoint goes, but look at the detail;
Per 100 grams of product, it has 275 calories and 37 grams of sugar (9 teaspoons) which is basically drinking a can of coke, (albeit, it does contain some fibre which coke doesn't, but still.....)
Take that in contrast with 100 grams of actual strawberries, which have 4 grams of sugar and 33 calories.
It's interesting how these companies go on about 'no added nonsense' 'no added sugar, etc, etc' when all they do is have a mechanical process that boils down fruit, until theres practically
nothing left other than sugar, then claim it's a natural healthy product.
I'm not suggesting that eating a pack of the above will make you 40 stone, but it's the sheer availability of these types of products, all claiming to be healthy, when in reality they're providing lots of extra calories, lots of added sugar, neither of which are a good thing.