Protocol for a meta-research study of protocols for diet or nutrition-related trials published in peer-reviewed journals: trends, advances, and reporting limitations

The "Standard Protocol Items: Recommendations for Interventional Trials" (SPIRIT) guideline establishes a minimum set of items to be reported in any randomized controlled trial (RCT) protocol, and the TIDieR (Template for Intervention Description and Replication) was developed to improve the completeness of interventions reporting in protocols and complete RCTs. Overall, reporting completeness of RCTs protocols have improved in general since the SPIRIT's publication. However, reporting completeness in protocols for diet or nutrition-related RCTs has not been systematically investigated. The purpose of this systematic review is to identify protocols of diet or nutrition-related RCTs published in peer-reviewed medical journals over time, to assess their reporting completeness and identify the main reporting limitations remaining in this field, despite SPIRIT and TIDieR.