Pat and I are on Atkins. I've been avoiding sugar for two weeks now. Oh, and also rice, bread, potatoes, and other carbs. But really, I don't miss those starches as much as I miss delicious pastries and fruit shakes.
First, the downsides. It's significantly more expensive. I'm eating more meat, but also more greens, and both are expensive compared to rice. It's also seriously depressing to go cold turkey on sweets, since normally I'm sugared up to the gills.
On the plus side, in those two weeks I've lost ten pounds! Maybe more! Ironically, I've also been getting better nutrients, because of all the fish and greens that I've been having. So hey, things are looking good.
In the long run, I think it's unhealthy to keep a strict ketosis diet, so I'll probably return to a broader diet... but I'll still skip out on white rice, white flour, and white sugar.