Instruments for evaluation of motivations for weight loss in individuals with overweight and obesity: A systematic review and narrative synthesis.

This systematic review aims to identify instruments used to assess motivations for weight loss in individuals with overweight and obesity from different age groups, such as children, adolescents, adults, and older adults. The virtual search was carried out using the PubMed, Scopus, LILACS, and ADOLEC databases, and by manual search. The following descriptors were used: questionnaire, scale, instrument, evaluation, motivation, motive, reason, "lose weight," "losing weight," "weight loss," and slimming. Methodological quality was assessed according to the criteria of the COSMIN checklist. The search yielded 3,524 results, seven of which were included in the review. Six questionnaires assessing motivations for weight loss, which could be applied to various age groups, were identified. All the questionnaires presented items related to appearance and health as the main motivation for weight loss. In addition to these motivations, the questionnaires also included items related to improved sports performance, self-confidence, participation in important social events, family and social pressure, and fitting into different clothes. The most evaluated measurement properties in the studies were internal consistency, reliability, content validity, and construct validity. Regarding internal consistency, one was rated as excellent, one as fair, and three as poor. For reliability, two were rated as being of fair quality, and one as of poor quality. Two studies analyzed the content validity and the questionnaires were rated as being of poor methodological quality. Regarding structural validity, one was rated as excellent, another as fair, and another as poor quality. Only the Weight Loss Motivation Questionnaire presented excellent methodological quality for most of the analyzed criteria. There is a need to develop questionnaires that are of better methodological quality to assess motivations for weight loss. Instruments targeting the adolescent population should also be developed.