Synthesis of intervention research to modify physical activity and dietary behaviors

A descriptive literature review was conducted to examine conceptual and methodological issues of interventions aimed at improving both physical activity and diet behaviors according to critical elements established by Sidani and Braden (1998). The method of the review of 30 articles describing 17 intervention studies focused on the following nine elements: (a) relevance of the intervention to the targeted outcome; (b) theoretical components of the intervention; (c) intervention components; (d) complexity, strength, and integrity of the intervention; (e) extraneous factors; (f) adherence to the intervention and retention; (g) reliability and validity of the outcome measures; (h) expected outcomes; and (i) effectiveness of the intervention. The results were that the interventions were relevant and included multiple components, but most interventions lacked an explicit theoretical framework. Adherence to the intervention and retention were problems. Overall, to varying degrees and for those completing the programs, the interventions were effective for increasing physical activity, lowering dietary fat, weight loss, and reducing risk for illness. Twelve "lessons learned" evolved that have practical and research implications. One salient lesson and future priority is to incorporate theory to reveal the intervention content and mechanisms to modify physical activity and dietary behaviors concurrently so that future interventions are more efficacious and efficient. Another lesson revealed the need for more sensitive measures, and examination of ways to improve intervention adherence and retention and prevent relapse.