How long can a star survive without food?

Stars don't consume food in the way living organisms do; instead, they generate energy through nuclear fusion, primarily converting hydrogen into helium in their cores. A star's lifespan depends on its mass—more massive stars burn through their fuel quickly and may live only millions of years, while smaller stars like red dwarfs can survive for tens to hundreds of billions of years. Once a star exhausts its nuclear fuel, it undergoes various evolutionary stages, eventually leading to its death, which can take millions to billions of years depending on the star's characteristics.