I think it's crap too, there is no way anyone can burn 500 calories every time you BF. It's just not possible.
What is your diet like? If you are eating more whole foods that are not calorie dense, then you should be able to eat a larger volume of food (especially if you are eating mainly fruits and veg). I'm really working on eating clean right now, and it's pretty hard. I've had slip ups every day this week so far. I'm just doing my best for now, and working towards my eating becoming cleaner every day. I guess what I'm trying to say is don't beat yourself up, just keep working towards your goal. You will achieve success if you do this.
I have heard of some women actually holding on to a little extra weight while BFing. My sister is actually having that struggle - she is working out regularly, eating right, but just can't seem to drop those last few pounds.
I lost a lot of weight in the first 2 months and then it started to slow down. Around 6 months, DS started eating a lot more and I started producing more milk to accomodate how much bigger he was getting. I lost a lot of weight right around that time.
GL - 15 pounds isn't too much and I'm sure you'll get the weight off!
I feel like I could have written this post myself. I have around 15lbs to go to start to feel more like myself and while I can button my jeans its not pretty. I think BFing does help you lose the weight, but I also am finding while I'm home on maternity leave I'm spending a lot more time sitting on the couch and snacking that I don't do when I'm at work. I'm sure this is off-setting whatever calories BFing is burning.
Also, make sure you're getting enough to eat, if you're hungry all the time your body will go into 'starvation' mode and hang on to that body fat. Eat every two hours - just make sure its healthy foods Good luck, I hope we'll both be comfortably in those jeans soon!