A Gourmet is a person of refined taste, with an in-depth knowledge of haute cuisine; in other words, a connoisseur of food and drink.
Thus, a Gourmet enjoys savoring high-quality food of elaborate taste and exquisite selections of matching wines and other suitable drinks, usually served in small portions, although being rather expensive alternatives of more common recipes.
A gourmet is not to be confused with a 'gourmand', who is a person who likes food and drinks but in rather large portions and eats lots and lots.
Gourmet is also a notion different from a person, rather a cultural ideal, associated with the culinary arts of fine drinks and refined, elaborate food preparations and presentations of aesthetically balanced meals.
As such, we can distinguish such notions as Gourmet Pasta, or Gourmet Cheeses, as well as certain places where such culinary experiences can be enjoyed, as Gourmet Restaurants, or even, in-extremis, Gourmet Street Food.
To conclude, for an enthusiast such as a gourmet, food is simply Edible Luxurious Art. Gourmets don't appreciate only the nutritional value of a meal, but in turn, they also enjoy the whole experience of eating, making, and displaying food differently.
References: Read Gourmet's definition on Merriam-Webster's Dictionary here