来自古代神话中的一个怪兽----饕餮（taō tiè）。 原意是指“贪婪”，但现在却指那些特别会吃，对美食文化和传统很了解的人。 是从原来的贬义转变为褒义的词汇。

It depends on the tone and context of it being used. It's like "you little imp!" A 饕餮 is a mythical beast that has a mouth but no posterior. It eats everything and nothing comes out. It is a good luck motif found on ancient bronzes to signify the wealth and prestige of the owner.

I did a search (because I'm curious myself). The two guys above are right. The definition of "glutton" I think is 贪吃 not 贪心，someone who is greedy when it comes to eating (I could be wrong though). Here's the link: https://baike.baidu.com/item/%E8%80%81%E9%A5%95/14215241

现在通常用于指“很爱吃，而且很会吃，能吃出门道”的人。

对古人来说是贬义词，在现代逐渐改为褒义词。指爱吃美食的人