X-Post - Help with Exercise and Weight Gain

I'm hoping that someone can help me figure out what's going on. 

I am 3 years post op and have managed to maintain my loss until I started seeing a personal trainer about 6 weeks ago.  I meet with her 3 times a week and my workout consists of lifting weights for 15 minutes and cardio for 15 minutes.  I also walk at least 4 times a week.  My eating has not changed.  I consume between 900 to 1200 calories a day with 50% being protein.  The other calories come from whole grains, vegies and fruit.

I understand that building muscle can add weight, but after 4 weeks, I expected to start losing weight again.  I have gained approx 10 pounds - my clothes are fitting the same, maybe even a bit loose.

Any ideas/suggestions?  My trainer has never worked with a GB patient before.

It just seems like someplace you are losing inches.  As I was dropping the weight I would lose it first where I had packed it on last...My back.  Also my moobs (man boobs) was one of the last things to go.  Make sure you are eating good carbs...esp watch the portion size of the carbs. 

Throw your scale away! You are losing inches and most likely dropping body fat %. Muscle weighs 3 x's more than fat so don't be a slave to your scale and DO NOT let yourself believe that your weight is your only measure of success. I had 14% body fat when I got to my lowest weight. I am now about 20-25 pounds heavier, but am at 10% body fat and wear the same size slothes. I like where I am at now, even though I WEIGH more than  I did, and I am in MUCH better shape now...

abbie,
i totally just posted almost the same exact thing!!!!!!
i don't use a trainer but have been doing my own workouts.  i'm only a little more than a year out but i'm scared i'll never get to my goal of 150 because of this....
rebecca

I agree with Dan completely. In the last few months I have focused on building muscle and have gained wieght while losing inches. Don't use your scale at this stage , judge by how you feel and how your clothes fit. Weight is just a # that doesn't mean anything compared to health.

If your clothes are looser, you've lost fat. Which is all the matters.

Let's put it this way, for Ironman 2, Robert Downey Jr. gained 20 lb. of muscle. Yeah, he was 20 lb. heavier on the scale, but he was RIPPED. Once you get down to a normal weight, the scale gets less accurate as a measure of health. Body fat % is a much better measure at this point.

Thank you all for your input. I really appreciate it.