I'm not sure from your post if you mean to say that you are not hungry, or that food tastes aren't appealing to you, or that you have lost your appetite because of illness.
If you are not hungry, there is no reason to eat. A lot of people are prompted to eat because the clock says it's time for a meal, but that isn't necessary. If you are eating unprocessed foods, hunger and satiety are good indicators of when and how much to eat.
If you don't feel interested in the taste of unprocessed foods (such as the ones you mentioned) and have been eating this way for a while, eat when hungry just for the sake of satiety. I'm sure that our paleo ancestors often ate out of hunger - for example, they ate a bunch of gophers when they'd much rather have a bison. Commercial food promotion has us thinking that everything we eat has to be an out-of-this-world taste experience. Does it?
If you are sick and don't feel like eating, give it a rest.
What else do you do each day? Are you really enjoying your life?
