Organizations worldwide are under increasing pressure to advance diversity, equity, and inclusion (DEI), yet despite years of strategic investment, meaningful progress has been slow — gender pay gaps persist, leadership remains largely homogenous, and underrepresented groups continue to face systemic barriers. This guide explores why traditional 'crash diet' approaches to DEI fail to create lasting change and why a sustained, systems-level mindset is required. Using experience management (XM) technology and integrated employee experience (EX) programs, HR leaders can uncover critical insights, close experience gaps, and drive measurable inclusion outcomes. The guide provides practical frameworks for embedding DEI practices into existing EX programs, from defining key terms such as diversity, equity, inclusion, and belonging, to applying systems thinking across the organization.