noun
A person who appreciates and is knowledgeable about fine food and drink; a connoisseur of haute cuisine.
彼はガストロノームとして、世界中の高級レストランを巡っている。
As a gastronome, he travels around the world visiting high-end restaurants.
グルメ is a more common, everyday term for a food lover or gourmet, while ガストロノーム is a rarer, more formal or literary term emphasizing deep culinary knowledge.
食通 is a native Japanese term for a gourmet or epicure, often used in casual contexts, whereas ガストロノーム carries a European, sophisticated nuance.
Borrowed from French 'gastronome', ultimately from Greek 'gastronomos' (stomach + law/rule).