Olanzapine to Abilify weight gain

I’ve been on olanzapine for about a year and gained like 40 pounds, so I’ve been thinking of switching to ability to see if that would help. I keep reading posts of how others also gained weight on ability, and others of how they lost weight when they switched. Is it possible to gain more weight if I do decide to switch? Or since I already gained the weight will it neutralize it.