Randomised controlled trials (RCTs) and quasi-experimental studies of interventions for increased physical activity participation based on one or more psychosocial theories were included in the review. Single groups studies with a pre-post-design were excluded from the review. Also excluded were interventions that used weight loss pharmacotherapy, herb or natural products, very low calorie diets, meal replacement or food provision, structured physical activity programmes or diets. Trial participants were required to have a mean body mass index (BMI) of between 25 and 39.9 kg/m2 and a mean age between 18 and 64 years. Studies of participants with known mental disorders, physical diseases or specific populations were excluded with the exception of those that targeted individuals with diabetes, related metabolic syndromes, hypercholesterolaemia or hypertension. Studies were required to follow participants up for at least three weeks without therapeutic participant contact.
Included studies enrolled patients with mean BMIs that ranged from 29.7 to 37.9 kg/m2 and mean ages between 37.7 and 55.1 years who were mainly female and Caucasian. One study targeted African Americans and patients with hypertension whilst two enrolled patients with diabetes. All except three of the studies, which were focused on increasing physical activity, had primary aims of weight management. Most studies assessed physical activity subjectively by methods such as self-reported questionnaires; objective assessments used pedometers, accelerometers or physical fitness indicators
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.