I've been on a few bcp's... and, seriously, they're as variable as diets! One may do wonderful things for one person, and TERRIBLE things for another...
lol get ready for my mini-novel of bcp's
lol it kind of reads like "if you give a mouse a cookie.."
I started (and am back on) the patch: I lost 30lbs while on it 5 years ago, and am glad to be back on it now.
I used the ring, which was fine, but it made me feel super bloated and constipated ALL the time...
So I moved to FemCon (FE) the "iron" pill-- which gave me TERRIBLE side affects-- mostly just making me sensitive.. everywhere.
Then I went to a "generic" pill that had the same sorts of hormones as the patch, but that sucked...
So I tried the chewable pill (I'm not much of a pill swallower anyway), and I was told that I was "PMSing 3 weeks out of the month, and Bi-Polar 'that week'" (bad news!)
Lastly I tried YAZ, and it was fine... but (and not sure if this is related..) I grew an enormous ovarian cyst while on it (like bigger than a basket ball) and am currently recovering from surgery. My aunt (who, coincidentally was on YAZ at the same time) was hospitalized for blood clots (again, coincidentally, the same day I went in for surgery) -- So my family is kinda Anti-Yaz.
Gotta stress, though--this is one FAMILY's experience-- this doesn't mean that this will happen to you!!!
So now I'm back on the patch
Anyhoo-- beyond my long-winded story about bcp's-- normally people don't find that they gain more than 5lbs of "water weight" when they start a new bcp-- and if you diet and exercise, it goes away pretty fast!
I don't know that any bcp's "help" with weight loss... but-- I guess it's more of a matter of "which hinders the loss the least"... And, again, it's going to depend on you: Because your hormones are different from mine (etc etc)
If you're not wanting to take bcp's because of weight gain, a tried and true birth control is condoms!
And there are other non-hormonal methods like diaphragms, and IUD's.