This paper synthesises the key findings of past separate studies conducted by the same authors, which sought to assess the efficacy of the Reading to Learn (RtL) literacy intervention on students' academic writing performance. Both studies of RtL were implemented in response to growing concerns about the academic under-preparedness of undergraduate students at universities across South Africa. The first study aimed to support mostly first-generation, first-year English Additional Language (EAL) learners in their transition to higher education. The second study aimed to support EAL students' academic writing development at a senior secondary school level prior to the school-to-university transition. In both studies, the cohorts of students examined originated from low socioeconomic communities, where linguistic marginalisation arguably imposes significant barriers to successful university completion. The novel contribution of this paper is to use a Cognitive Load Theoretical lens to explicate why RtL might improve the academic writing skills of under-prepared students making the transition to university.