The first two are correct because they are in the present perfect tense. Your second two options are incorrect.

I'm not sure about the grammatical point here but l feel like the meaning is slightly different. As far as I know the present perfect continuous, have been eating/smoking, gives a sense or a meaning of doing the thing continuously.In your first example, I haven't eaten for an hour, means it's now 7 oclock and I haven't eatne anything since 6 oclock. However in I I haven't been eating for an hour, I get the feeling that you have eaten and stopped eating in this hour.

I hope that makes it clearer and as i said at the beginning this is just my understanding of the tenses.

In my opinion all four are correct. First two are present perfect and second two are present perfect continuous.