I think its a shame and mistake to think of all carbs as bad and the general demonising of healthy carbs. Beans are very nutritious and comparatively low calorie. they are not just carbs but high in protein.
The carbs that should be demonised are refined carbs like white bread, cakes, sweets, puddings, and all sorts of bought and processed ones.
Yes you can get fat on wholegrain bread, pasta and rice and beans but you have to eat a lot of them unless you load them up with fatty extras like cream, oil and butter and fatty meats.
So its good to know you liked this dish a lot but i'm struggling to imagine it. I'm not a big fan of cooked celery or roasted carrots but it sounds worth checking out since you liked it so much.