Eleven studies were included in the review (n=2,502): seven randomised controlled trials (RCTs, n=1,139), two non-randomised trials (n=508) and two uncontrolled case series (n=855). Overall, the quality of the included trials was considered to be weak.
Five RCTs found a significant difference in mean weight loss or change in BMI in intervention groups compared with controls. Mean difference in weight loss ranged from -0.2kg to -6.4kg. All four high-intensity programmes (three RCTs, one uncontrolled case series) resulted in significant weight loss. One of the five low-intensity programs, an RCT, reported a significant difference compared to controls. One RCT looked at maintenance and found significant weight regain in both intervention and control groups at 12-week follow-up.
In general, modest improvements were reported for effect on serum lipids and changes in systolic and diastolic blood pressure; only two RCTs found a significant improvement in systolic and diastolic blood pressure.