1. The first low carb diet book was written over 100 years ago. Hardly a fad because it seems to be around for a while.
2. The Atkins diet is a strategy that helps you eat less by reducing cravings. A strategy is not a fad.
3. People stay on Atkins for many years sometimes even a lifetime.
4. The Atkins diet improves ones health in terms of lowering cholesteral and other ways of measuring health.
5. There are many doctors that can answer any and all questions about a low carb diet. For example Dr Michael Eades is an excellent source for information about a low carbohydrate lifestyle.