Star-Crossed — Pintip Dunn

In a world where nutrition can be transferred via a pill, and society is split into Eaters and Non-Eaters, seventeen-year-old Princess Vela has a grave dilemma. Her father, the king, is dying, and only a transplant of organs from a healthy Non-Eater boy will save him.

Vela is tasked with choosing a boy fit to die for the king, which is impossible enough. But then Carr, the boy she's loved all her life, emerges as the best candidate in the Bittersweet Trials. And he's determined to win, because by doing so, he can save the life of his Non-Eater sister.

Refusing to accept losing the boy she loves, Vela bends the rules and cheats. But when someone begins to sabotage the Trials, Vela must reevaluate her own integrity―and learn the true sacrifice of becoming a ruler.