Dietary therapy is one of the key measures for weight management in overweight and obese populations. Research evidence indicates that, compared with other dietary treatment options, the very low-calorie ketogenic diet (VLCKD) exhibits significant advantages, including the evident short-term effect of weight loss and improvement of insulin resistance, showing considerable potential for clinical applications. However, there are still controversies regarding the role of VLCKD in regulating blood lipids, improving comorbidities, and achieving long-term weight loss, as well as the severity of its side effects, thereby complicating its clinical application. Therefore, based on an overview of the concept and clinical applications of VLCKD, this article focuses on the impact of VLCKD on weight, blood glucose, blood lipids, and other diseases in obese individuals, as well as the generation and prevention of side effects, aiming to provide references and evidence to support clinical dietary treatment for obesity.