Whenever I’m asked whether a certain food is healthy, I invariably reply: ‘Compared to what?’
For example, are eggs healthy? Compared to oatmeal, definitely not. But compared to sausages next to them on the breakfast plate? Yes. What about potatoes? They’re vegetables, so they must be healthy, right? Compared to French fries, yes. Compared to a baked or mashed sweet potato? No, they’re not.
I realise these may not be satisfying answers, but the only way to answer the question meaningfully is to ask what your other options are. If you’re in a fast-food restaurant, for example, a baked potato may very well be your healthiest option.