For some reason, our cat used to be absolutely crazy for anko. The first time he ever encountered it, he stole a dorayaki out of someone's hands and hid with it in the closet growling (it was wrapped in plastic so he couldn't actually eat it). After that, I used to give him a tiny taste any time I had some but I noticed he would always throw up soon after. Now that he's a bit older he seems to have no interest in it at all.

Could it be that they can taste sweets at a young age but gradually lose that ability?