I’m sure people have been trying to do this for many years! Part of the problem is that we still have part of the mind set of a hunter-gatherer. This means that when we find foods with lots of fat and sugar we eat a lot of it in case we have to survive a time when we can’t get anything to eat. (We don’t have this problem in the westernised world today, so don’t lose the weight but don’t stop eating either, leading to obesity.)
This means that we like foods with lots of fat and sugar in, neither of which are particularly good for us in large amounts making it difficult to create a food that everyone will eat that is perfectly healthy for us. Apparently if you try eating a type of food either 7 or 10 times (not sure exactly which, but perhaps you could test this and let me know) you will like it – so next time you have to eat a vegetable that you don’t like, grimace for a bit and think that if you eat it just a few more times you won’t hate it as much and may actually enjoy eating it!
As Marcus said, we naturally like things that are full of fat and sugar. If you watch any cookery show, it’s not rocket science that their food is tasty – it’s usually full of butter, salt and sugar!
I think there are lots of formulation chemists working on flavourings – but I’m not sure that all of the work is to try to make flavoured healthy food – more like exotic ice cream flavours judging by the latest supermarket adverts! Lots of healthy foods do taste nice already – it’s just sometimes grabby a chocolate bar is easier than some fruit!