Everyone has a favorite food, and they can like it for all kinds of reasons. Obviously, it could be the taste. It could also be a happy memory associated with the dish. It might even be a special treat provided by a friend. In this regard, food is not just about sustenance but also happiness. This type of love for food might also be observable in Naruto's eponymous main character.
Naruto Uzumaki loves ramen. Like a lot. He's constantly seen eating at Ichiraku Ramen with his friends and mentors. Knock on his door in the morning and he'll probably answer with a cup of instant ramen in his hand. When he introduces himself, the two big things he talks about are what kinds of ramen he likes and becoming Hokage. It's practically the only thing he's ever seen eating; if Kakashi didn't pop by his apartment occasionally to give him vegetables, it might actually be the only thing he ever eats. That and red bean soup. The Only other characters who can eat more ramen than Naruto are Yamato and Hinata. Finding out the reason or reasons for this borderline addiction will require a closer look at Naruto as a whole.
The most obvious reason for Naruto's love of ramen is that it fits his design motif. Naruto may love ramen, but what he's really all about is spirals. As such, the spiral motif is present throughout the Naruto franchise. The logo of the series is superimposed over a spiral. Kana-Boon's theme for Naruto Shippuden: Ultimate Ninja Storm 4 is "Spiral." The iconic Rasengan (螺旋丸) can be translated as "Spiral Chakra Sphere." In the Road to Ninja movie, Naruto loses his memory and gets it back by looking at a rolled-up scroll. There are also all kinds of markings and Jutsu seals (eg Naruto's Tetragram Seal) that utilize a spiral pattern.
Naruto's own Uzumaki clan is also all about spirals. And whirlpools, which are shaped like spirals. Their family name means "Whirlpool" or "maelstrom;" they come from the Land of Eddies; the family crest, which Naruto coincidentally wears on his back, is a spiral. This doesn't have anything to do with ramen yet, but it will.
Ramen pertains to Naruto's spiral motif because of one of its key ingredients- the narutomaki. This fishcake is often placed at the top of a bowl of ramen noodles; its cloud shape and red spiral design have become practically synonymous with the dish itself. It also happens to be one of Naruto's favorite parts of ramen. His love for this fish cake in particular is to the point where he sulks when there isn't one in his bowl (albeit in a straw-that-broke-the-camel's-back manner).
As for in-universe reasons for Naruto's love of ramen, it may trace back to his name. Narutomaki sounds like a portmanteau of Naruto and Uzumaki. In fact, Naruto's parents chose his name based on the main character from one of Jiraiya's books; Jiraiya, in turn, thought up the name while eating a bowl of ramen. This doesn't necessarily explain where Naruto's love of ramen comes from, though it could have strengthened it after learning more about his parents and his master.
One possible explanation for Naruto eating at Ichiraku all the time comes from an anime end credits sequence. Naruto: Shippuden ending 34, "Niji no Sora," shows a young Naruto being invited into the shop by Teuchi and offered a bowl. From there, Naruto is shown throughout his life frequenting the shop with friends. Other customers include Naruto's parents and mentors like Iruka and Jiraiya. This ending even feeds into the idea of Hinata being able to eat much more ramen than Naruto; as she's piling up bowl after bowl, Naruto nearly hurls from overeating. This isn't entirely canon to the manga, but it's too wholesome to not consider.
While the manga never specifies what makes Naruto love ramen so much, there are plenty of ways to explain it. It ties heavily into his spiral motif. He also has fond memories of frequenting Ichiraku with people he cares about in both the anime and manga. Whatever Naruto's reason to start eating ramen, he's made too many good memories with the dish to stop.
