Britney Spears - How much weight should I gain because I weigh 82 pounds?

Well, depending on how old you are 82lbs is healthy. If you are 8-10, 82 is a good number, if you are 11-14, you should be about 100-125. 14-16, you should be almost fully developed and should weigh anywhere from 125-145. This is scale however is NOT for everyone. People have different body types and should NOT try to change because society says we should. Best wishes :)