Objectives: This study identified and reviewed grey literature relating to factors facilitating and inhibiting effective interventions in three areas: the promotion of mental health and well-being, the improvement of food and nutrition, and interventions seeking to increase engagement in physical activity.

Study design: Sourcing, reviewing and analysis of relevant grey literature.

Methods: Evidence was collected from a variety of non-traditional sources. Thirty-six pieces of documentary evidence across the three areas were selected for in-depth appraisal and review.

Results: A variety of approaches, often short-term, were used both as interventions and outcome measures. Interventions tended to have common outcomes, enabling the identification of themes. These included improvements in participant well-being as well as identification of barriers to, and promoters of, success. Most interventions demonstrated some positive impact, although some did not. This was particularly the case for more objective measures of change, such as physiological measurements, particularly when used to evaluate short-term interventions. Objective health measurement as part of an intervention may act as a catalyst for future behaviour change. Time is an important factor that could either promote or impede the success of interventions for both participants and facilitators. Likewise, the importance of involving all stakeholders, including participants, when planning health promoting interventions was established as an important indicator of success.

Discussion: Despite its limited scope, this review suggests that interventions can be more efficient and effective. For example, larger-scale, longer-term interventions could be more efficient, whilst outcomes relating to the implementation and beyond could provide a clearer picture of effectiveness. Additionally, interventions and evaluations must be flexible, evolve in partnership with local communities, and reflect local need and context.