Like most animals, guinea pigs have a drive to seek out variety in their diet. They will most eagerly eat food they haven't seen for a while, and can avoid foods they have seen a lot of. Swap peppers for something else for a week, and she will probably become keen on them again.
buddy will eat anything and everything and never get tired of anything lol.. Lucy stopped eating carrots and peppers. She loves GRASS, Lettuce and apple, I have tried brocoli and she has eaten a lil bit but that doesnt really do much for her i guess. I'm not sure what else I could try that she would like.