Low carb diets were claimed to be dangerous for many years. The Atkins Diet was singled out in particular, mostly on account of the fact that it is a ketogenic diet (meaning that ketones are produced as a by-product of burning fat for energy) and that it is high in fat.
However, concerns about low carb diets and the Atkins Diet have now been proved to be myths that were unsupported by science. In actual fact, more and more clinical studies are reporting that indicators of future problems such as cholesterol and blood pressure improve on low carb diets such as Atkins.
Nevertheless, the Atkins and other low carb diets have not as yet been given the formal seal of approval by government health departments. This is because they do not conform to existing healthy eating guidelines which say that the only healthy diet is a low fat diet based on grains. It will take many years before the official healthy eating guidelines are changed, despite the fact that many experts think they are wrong. Read "Are Our Healthy Eating Guidelines Wrong" for further information.
The "Easy Guide to Low Carb, Low GI & Low GL Diets" explains more of the background to the undeservedly bad reputation that low carb diets acquired, and the science behind them.