The stomach is elastic and has the capacity to stretch. Hence, the residual sleeve also will stretch. The extent to which these stretches vary. In the long run as the intake of food increases and if lifestyle modifications are not followed, this could be a reason for weight regain. If the band is applied after creating the sleeve, then the extent of stretching of the stomach wall below the band will be very little. Also, the band is non-adjustable and hence it acts as a valve controlling the passage of food, thus allowing the food to pass down slowly, in turn, restricting the intake of food.
Thus, the sleeve is banded in those having a very high BMI, thus ensuring continued weight loss and long-term maintenance.