The use of very low energy diets has been through several phases. The first phase was consumer driven, not medically supervised, and proved to be unsafe. The second phase involved modifications to render these diets safe and the institution of programs to ensure proper monitoring and to provide organized behavioral modification programs. While the popularity of very low energy diets grew in these supervised programs, not enough attention was paid to long-term results and many patients regained their weight. This has led us to the current phase of very low energy diets with proper attention to maintenance and to the appropriate use of very low energy diets to treat uncomplicated and complicated obesity. There is definitely an important role for very low energy diets in the treatment of obesity, a chronic illness associated with significant health hazards.