Study designs of evaluations included in the review
Explicit inclusion criteria for the study design were not defined. Randomised controlled trials (RCTs) and quasi-RCTs were included. The participants were randomised at a group or individual level.
Specific interventions included in the review
Studies that included both physical activity and dietary behaviour in naturalistic settings were eligible for inclusion. All interventions were defined as complex and included an educational and a behavioural change component. Some studies were guided by explicit theoretical models. The control interventions were usual care, self-help guides, waiting-list control and no treatment. Components of the intervention were categorised as education to change knowledge or attitudes; behaviour change strategies to overcome barriers or facilitate behaviour change; social strategies to provide support or a supportive environment; or organisational strategy. The interventions were administered in individual or group sessions for a duration of 5 months to 5 years, and the intensity of them varied between 42 and 52 sessions.
Participants included in the review
Studies of healthy adults, aged 18 years or older, were eligible for inclusion. Details of gender, age, ethnicity, and profession or social status were reported, along with characteristics of individual and environmental factors that might influence change. The included studies were conducted in communities, worksites, weight-loss or medical clinics, or a combination of these.
Outcomes assessed in the review
Explicit inclusion criteria for the outcomes were not reported. The included studies assessed the effectiveness of the intervention in relation to diabetes prevention, weight loss, hypertension prevention, or general healthy behaviours to prevent chronic illness, mainly using self-reporting questionnaires or diet and physical activity diaries. Details of the reliability and validity of outcome measures used in each individual study were reported.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.