I have twice used the
atkins diet to completely remove all carbs (not sugars) from my diet. The key I found was that I went cold turkey on carbs, rather than moderated. Both times I was able to sustain it for about 18 months. Unfortunately, when I tried to moderate (ie add in some carbs to my diet), I fell off the wagon and started to eat ice cream and pizza way too much.
Also, I would think it is near impossible to use the atkins diet if you're a vegatarian. Much of my food consisted of steak, cheese and salads.