Introduction: In the last years, confusing or misleading use of the term called miracle or magic diets, using to weight loss treatment, has increased, along with several classification of them. Objectives: The purpose of this narrative review is to discuss miracle slimming diets and proposal new term and new classification for these diets. Methods: A narrative review up to September 2021 was carried out in the PubMed, Google Scholar, and Web of Knowledge. Furthermore, this strategy was complemented with a comprehensive search of the 'grey' literature [7] based in four different searching strategies: i) grey literature databases, ii) customized Google search engines, iii) targeted websites, and iv) consultation with contact experts. Results: Our proposal is to use the new concept called hazardous slimming diets defined as diets that propose rapid weight loss (> 1 kg/week), to be performed effortlessly, without the super-vision of a medical/nutritional professional, excessive energy restrictions and/or exclusion from the di-et of food or nutrients for the body. Furthermore, the development of a new algorithm reflected as is possible to classify the diet as non-effective, hazardous and effective diet. Conclusions: Our review could help to classify and develop a new terminology about the miracle slimming diets focusing in the knowledge to guarantee the quality in the treatments for weight loss.