My diet was more extreme than Atkins and I felt great. And from comments I received, I'd say that I looked just fine.
But we're all different.
The important thing to remember with Atkins is to have regular blood tests to make sure your LDL cholesterol is under control. I would not stay on it long term since you can miss out on a lot of foods that have cancer-fighting properties. But I would recommend it to anyone who wants to get a good start on significant weight loss.