Shous, everyone's body's different, so only you will know how many servings of beans you can have a day without causing cravings or weight gain, but I've never limited my bean intake and it's never been a problem. I sometimes have 2-3 servings (or more) a day of various beans. They are really helpful in SBD even if you like meat, as they provide fiber (to keep you from the constipation that can sometimes be an issue on SBD), good carbs (even in P1...and that keeps you from dealing with some of the side effects of detoxing from sugar), and protein.
If you don't like meat, there are other options besides beans on SBD. You're allowed tofu and tofu products along with other vegetarian options. Check out the Good Fats, Good Carbs Guide for more info on what in particular is okay...or check the Foods to Enjoy/Avoid lists in our FAQ. You can also post a question about vegetarian eating on SBD or search for past posts on the subject. I know of a couple of vegetarian SBDers...only Mauvais (who has done a WW/SBD combo) comes to mind at this moment, though. You can also check with the Alternachicks forum on 3FC...they have a veggie section there.
Hope you'll be joining us!