Are mindfulness-based interventions beneficial on improving psychological and physical health outcomes among overweight or obese adults?
Date of publication of the systematic review: January 2017
Design
Systematic review of 7 randomized controlled trials (RCTs).
Participants
560 adults, who were overweight or obese, defined as > 25kg/m2 (mean age: 45.79 years). The reviewers did not report gender proportion of the participants.
Intervention
Acceptance and Commitment Therapy (ACT) or mindfulness-based treatments (e.g. mindfulness-based stress reduction and mindfulness-based cognitive therapy) were used as interventions. Length of each session ranged from 20 minutes to a full-day workshop, and duration of the intervention ranged from 4 to 40 sessions.
Comparator
Comparison: ACT or mindfulness-based intervention versus waitlist control, active psychological intervention or usual behavioral treatment.
Major Outcomes
Outcome 1: Post-intervention body mass index (BMI);
Outcome 2: Post-intervention anxiety as measured by the Beck Anxiety Inventory. Higher scores indicated higher anxiety level;
Outcome 3: Post-intervention eating attitudes as measured by Three-factor Eating Questionnaire. Higher scores indicated poorer eating attitudes;
Outcome 4: Post-intervention eating behaviors as measured by Binge Eating Scale. Higher scores indicated eating behaviors more proximal to binge eating.
Settings
The included trials were performed in an outpatient setting.
Comparison    ACT or mindfulness-based intervention versus waitlist control, active psychological intervention or usual behavioral treatment
Main Results
Compared to waitlist control, active psychological intervention or usual behavioral treatment, ACT or mindfulness-based treatments reduced BMI (g: 0.43, 95% CI: 0.21 to 0.65), anxiety as measured by the Beck Anxiety Inventory (g: 0.53, 95% CI: 0.25 to 0.82). It also improved eating attitudes as measured by the Three-factor Eating Questionnaire (g: 0.48, 95% CI: 0.18 to 0.78) and eating behaviors as measured by the Binge Eating Scale (g: 0.53, 95% CI: 0.01 to 1.05).
Comparison: ACT or mindfulness-based intervention versus waitlist control, active psychological intervention or usual behavioral treatment among overweight or obese adults
Outcomes (units) No. of studies (Total number of participants) Mean value/No. of participants Heterogeneity test (I2) Hedges’s g (95% CI) p value Overall quality of evidence*
Intervention Comparator
1 (kg/m2) 5 (341) Not reported/173 Not reported/168 Not reported 0.43 (0.21 to 0.65) <0.01 Moderate
2 (NA) 2 (192) Not reported/95 Not reported/97 Not reported 0.53 (0.25 to 0.82) <0.01 Low
3 (NA) 4 (165) Not reported/84 Not reported/81 Not reported 0.48 (0.18 to 0.78) <0.01 Low
4 (NA) 2 (106) Not reported/55 Not reported/51 Not reported 0.53 (0.01 to 1.05) 0.05 Low
Keys: CI: confidence interval.
Comparison    ACT or mindfulness-based intervention versus waitlist control, active psychological intervention or usual behavioral treatment
Main Results
Compared to waitlist control, active psychological intervention or usual behavioral treatment, ACT or mindfulness-based treatments reduced BMI (g: 0.43, 95% CI: 0.21 to 0.65), anxiety as measured by the Beck Anxiety Inventory (g: 0.53, 95% CI: 0.25 to 0.82). It also improved eating attitudes as measured by the Three-factor Eating Questionnaire (g: 0.48, 95% CI: 0.18 to 0.78) and eating behaviors as measured by the Binge Eating Scale (g: 0.53, 95% CI: 0.01 to 1.05).
Comparison: ACT or mindfulness-based intervention versus waitlist control, active psychological intervention or usual behavioral treatment among overweight or obese adults
Outcomes (units) 1 (kg/m2) 2 (NA) 3 (NA) 4 (NA)
No. of studies (Total number of participants) 5 (341) 2 (192) 4 (165) 2 (106)
Mean value/No. of participants Intervention Not reported/173 Not reported/95 Not reported/84 Not reported/55
Comparator Not reported/168 Not reported/97 Not reported/81 Not reported/51
Hedges’s g (95% CI) 0.43 (0.21 to 0.65) 0.53 (0.25 to 0.82) 0.48 (0.18 to 0.78) 0.53 (0.01 to 1.05)
p value <0.01 <0.01 <0.01 0.05
Overall quality of evidence* Moderate Low Low Low
Keys: CI: confidence interval.
Conclusion
Benefits
Compared to waitlist control, active psychological intervention or usual behavioral treatment, ACT or mindfulness-based treatments provided beneficial effects on BMI, anxiety, eating attitudes and eating behaviors. For outcome 1, the overall quality of evidence is moderate. Further research is fairly likely to have an important impact on our confidence in this estimate of effect. For outcomes 2 to 4, the overall quality of evidence is low. Further research is likely to have an important impact on our confidence in this estimate of effect.
Harms
The authors did not report on adverse events of the intervention.
Link to Original Article
https://www.ncbi.nlm.nih.gov/pubmed/27862826
The synopsis is based on the following article:
Rogers JM, Ferrari M, Mosely K, Lang CP, Brennan L. Mindfulness‐based interventions for adults who are overweight or obese: a meta‐analysis of physical and psychological health outcomes. Obesity Reviews. 2017 Jan 1;18(1):51-67.


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.