Are you kidding? "Алкать" is an extremely archaic word. To the extent it took me a few seconds to guess its meaning. Of course, there is a more common word derived from it - алчный "greedy, avid". Still, outdated but at least understood by native speakers.

In everyday speech use "Я голоден" ("I'm hungry"), "Я хочу есть" ("I want to eat"), "Хочу перекусить" ("Wanna have a snack") and so on, depending on the meaning. "Я проголодался" (lit. "I have grown hungry") may also work. After all, in Russian one rarely says "Я голоден". Too neutral, and doesn't really sound like "it's about time to eat".