Well, I guess the question is how did you gain the weight in the first place? If stopping keto means going back to how you ate previously, then yes, I would imagine the weight will creep back on.
The Atkins diet has people slowly increase carbs once they have reached their target weight. When they get to a point where they are no longer maintaining their weight loss, then that carb level is too high. You will need to find your level of carbs that will keep you from regaining your weight.