I think flickety has put it very well – fuss about diet being about looking for something to worry about. The thing is, in spite of all this worrying, life expectation is still higher than it's ever been. Age must have a lot to do with all these modern prevalent illnesses. Maybe we just didn't live long enough before and died of other things instead.
And, still, all the advice is, essentially, be moderate in your intake of anything and your risk of getting any of the currently prevalent diseases will be lower than if you overdo something. And get some exercise. And don't smoke.