Obesity has become a global "epidemic". At this stage, overweight / obesity has become a major public health problem that seriously affects not only adults but also children and adolescents worldwide. Medical nutritional therapy is the basic treatment for obesity and an indispensable measure for prevention and control at any stage in the course of obesity. Management of comorbidities and improving the quality of life of obese patients are also included in treatment aims. In recent years, there have been some guidelines on the nutrition management of overweight/obesity. However, the management of nutrition and lifestyle interventions must be compatible with specific regional dietary habits and social culture. To provide a clinical reference for the standardized treatment and management of overweight / obesity, guidelines for medical nutrition treatment of overweight/obesity in China (2021) were published, which cover the relationship of weight loss with different dietary patterns, meal replacement foods, biorhythms, intestinal microecology, metabolic surgery, and medical nutritional intervention, as well as weight loss in special populations. We hope the guidelines will improve the awareness of the importance of nutrition intervention in the treatment of metabolic disease, further regulate the principle and approach of medical nutrition therapy, and establish a workflow of standardized medical nutrition therapy for weight loss management so that more clinical nutrition professionals and medical staff can use it to provide better services for obese people.