Well, that's sort of to be expected. :-( All the foods you've mentioned are highly processed, and engineered to be shelf-stable, tasty, and use cheap, good tasting ingredients. I wouldn't even consider them food anymore, more like highly engineering edible dopamine stimulators.

Opposed to that, a grapefruit does not stand much of a chance. But if you kick processed sugars for a few weeks, things start slowly tasting better, or so I hear. I've been trying to do that, but sugar is in almost everything these days