I think the tummy issue after babies is somewhat genetic. I've always carried weight in my lower half (hips and butt). It doesn't matter if I'm at my ideal weight, overweight, or even too skinny, this is where it goes. I had 3 kids in 4 years (one didn't make it) and really did not have tummy issues after each. I had weight to lose, but it was from all over. My mom and my aunt were the same way. I think just doing crunches is boring and probably Pilates and/or Yoga would help, too.
Anorexia is very difficult. Society rewards us for looking "thin," but doesn't support us when it becomes a problem. About 20 years ago, I weighed 10-15 lbs. less than I do now. REALLY skinny. It was basically from over exercising, but my friends were constantly being asked if i had an eating disorder (which no one would ask if they really knew me, because I love to eat). The sad thing was that inside, I secretly liked people noticing how low my weight was. Once I stopped working at health clubs, the pressure to be so skinny was less.