BED-Vyvanse-Constipation

So recently I was diagnosed with binge eating disorder. My doctor prescribed me Vyvanse to help treat it. Vyvanse is also used as an ADHD/ADD medication. I've done research on general ADD/ADHD meds and learned that some can cause constipation. I've been keeping a daily log with this medication trial. I used to binge once or twice a week & since I've started Vyvanse I haven't really binge ate. I want to continue using Vyvanse, so what should I do about the constipation? Any tips that could help? I drink a lot of water and eat relatively healthy.