My grandma always referred to me as a "好吃jin(g?)" i.e. a glutton. However I'm not sure which character goes in the third one. This might be regional (Anhui) dialect, I am not sure, because I couldn't find an appropriate word in the dictionary or keyboard suggestions.
I would suggest 「好吃精」 (Mandarin Pinyin: hàochī jīng), where 「精」 is short for something like 「妖精」 (demon). 「好吃精」 then means glutton demon.
See also https://baike.baidu.com/item/好吃鬼, where 「好吃精」 is listed as a synonym.