Science diet or purina beneful?

Question: i have an english bulldog. he eats a lot. only feed him 2x a day bec he gets fat and i dont want him to be overweight. Now, ive been giving him science diet eversince, ive been trying to cut some of my budget, what will yall suggest as an alternative, having the same nutrients but cheaper? im thinking beneful? im open to suggestions. thank yoU!