First, I have never thought that just eating nutritionally sound is an instant magic pill for obesity. Whether emotional or something in our gut (see some of the newer mouse/gastric bypass results), and looking at the number of people who remain thin on SAD, the whole "eating healthy will make you thin," just doesn't wash for me. Eating healthy will make you healthy.
Having been down the low carb road before, and having known a lot of people who did this when Atkins first came out with his books, I heard over and over again that it worked for ~40 pounds, then calories came back into the picture.
If possible, maybe have your thyroid tested. Some doctors are becoming much more savvy in this area. Also, if you're on any medications, check with your doctor to see if they are interfering with your weight loss goals in any way.
Don't get discouraged, but do be your own science experiment and switch out foods, timing of meals, exercise, etc., to see what works for you. Good luck!
"Right is right, even if no one is doing it; wrong is wrong, even if everyone is doing it." - St. Augustine