My girlfriend is 5'5 and was weighing 172.5 pounds. My mom was going on a diet so my girlfriend wanted to also and she was very committed to it. She got to 150 pounds after about 4-5 months.

But she couldn't get past 150, and she actually gained some weight back and she is now 155. The weird thing is she gained 5 pounds within 1-2 nights and she has been eating exactly how she has been while she was losing weight. She has been working out a little bit extra, I'm not sure if you can gain more muscle that fast or not. She is still at 155 and it's been a week since she gained it.

She eats between 1250-1400 calories a day

Any ideas why that might have happened so I can help her out? She seems like she is getting down about it. Also any suggestions of how to keep losing weight would be great to.

It's possible she put on some muscle, which weighs more than fat.

Just tell her not to give up... it takes some time and determination to get over a weight loss slump.

If she really wanted to speed it up, it basically comes down to exercise if her diet is good. Get in the gym, join a sports team, etc... anything to get heavy activity a couple hours a week.

Could be water weight. Have her increase her water consumption.