Great Question.By changing your diet and exercise will benefit you more than any pill. As far as weight fluctuation could have some effect on your BBL. You could potentially loose and gain weight in the buttocks area if you are to gain or loose weight overall. Next step would be to schedule a follow up appointment with your board certified plastic surgeon to discuss your options and/or goals. Best of luck.
my guess is changing your diet will be a lot more effective than taking any form of pill.
It seems like you'v already describe the problem when you said your diet changed. So the underlying problem is not a lack of Garcinia but rather what and how much you're eating.
Good luck getting back on track.