The diet books make it sound easy. Cut the carbs, lose the weight, normalize your blood sugar, feel great. For many people, it works that way. But for many more it doesn't.
When I reviewed the research that went into my book, Diet 101: The Truth About Low Carb Diets I was surprised to learn just how poorly low carb dieters fared in the research studies that I had always seen cited in the low carb community as proving the diet superior to others.
Partly this is because few diets of any kind work well for more than a few months, and looked at in that time frame, the low carb diet often surpasses others in it's effectiveness.
But once most people get past the first six months of of their low carb diets, peer reviewed research and the posts of hundreds of people who visit online low carb discussion boards make it very clear that many if not most people see their weight loss stall out completely.
This doesn't have to be the case. There are a few, very interesting studies, that show that weight loss can continue on low carb diets, though at a much slower pace than dieters grew accustomed to during the first heady months of their diets.
Not losing weight is the most common form of "not working" that low carb dieters encounter. There are plenty of lists of "What to Do When you Stall" posted elsewhere on the web, in diet books, and even on this site, so I won't repeat them.
Check them out. If you haven't worked your way through the usual solutions, which include cutting back on calories, cutting out bogus "low carb" foods full of hidden carbohydrate, and eliminating certain other foods that tend to stall people, you can't really say that low carb isn't working for you.
But if you have tested all the stall breakers and still find yourself stuck way above your goal weight, yes, low carbing is NOT working for you, and continuing on, stuck in a stall, is a great way to end up depressing yourself to where you end up giving up and binging your way back to an even higher weight.
If this is your situation, there are several other things you can try.