Body Mass Index (BMI) is calculated by the weight of the person divided by the square height in meters. The BMI is an indicator about the body fat of a person. The research has indicated that BMI needs to be moderately correlated with the direct measures of body fat. It is also proven that BMI is strongly correlated with numerous metabolic and disease outcomes. These are considered to be an indice to measure the body fat. In general, BMI tool is an easy-to-perform method to comprehend about the weight category of the person. From a broad scope, higher BMI indicates that there is high level of body fat. This is used as a screening tool and not as a diagnostics tool. In this schema, it is important to comprehend the role of derivation of the BMI and related calculation. It is considered to be an important quantification analysis that is used to perform assessments and health screenings. Obesity is a health concern that impacts the people across the globe. A number of considerable researches have been undertaken to demonstrate the impacts and efficacy of weight loss and the strategies in the short term. The current paradigm of success with relation to the weight loss intervention focuses on the total weight loss at the end. The proportion of the participants in achieving the weight loss by percentage has been a clinically important criterion for success (Batterham, Tapsell and Charlton, 2016a). The single criterion does not factor in the weight loss for the different trajectories of weight loss over times. Growth mixture model is used in the psychology research to investigate the differential trajectories for the behavioural and psychological variables. These are used to track empirically the measured health outcomes as it is underutilized. These are some of the examples of the application that is used for the method of outcomes of clinical trials. From the past research, it can be construed that the numbers used to indicate weight loss. This is done to understand the impact of health the use of BMI tools that are beneficial. The different models that are currently used for the development of BMI models are explored in the following sections.