CBT-I linked to BMI reductions

A systematic review and meta-analysis published in *Obesity Reviews* found that behavioral sleep interventions, particularly cognitive behavioral therapy for insomnia, were associated with modest but statistically significant reductions in body mass index and body weight in adults with poor sleep health. The review was highlighted on May 13 by Endocrinology Advisor and Sleep Wake Advisor, which summarized results from trials involving adults with overweight, obesity or type 2 diabetes. The paper, led by Samiul A. Mostafa of the University of Birmingham and University Hospitals Birmingham NHS Foundation Trust, reviewed 27 studies published from 2011 through 2024, with 25 included in meta-analyses. The authors searched MEDLINE, Embase, CINAHL and the Cochrane Library through April 2025 and said 21 of the included studies were randomized controlled trials. (onlinelibrary.wiley.com) Across eight studies involving 1,384 participants, CBT-I and/or sleep hygiene interventions reduced BMI by an average of 0.64 kg/m2, with a p value of 0.0006, according to the review. By contrast, five sleep-extension studies involving 138 participants did not show a statistically significant BMI reduction, with an average change of 0.15 kg/m2 and a p value of 0.26. (onlinelibrary.wiley.com) In subgroup analyses, adults with obesity and adults with type 2 diabetes showed larger BMI improvements. The review reported an average BMI reduction of 1.53 kg/m2 in three obesity studies with 78 participants and 0.64 kg/m2 in three type 2 diabetes studies with 1,121 participants. Body weight also fell by an average of 5.55 kg in three obesity studies with 72 participants and by 0.83 kg in six studies involving 337 participants in the overweight range. (onlinelibrary.wiley.com) The same analysis found changes beyond weight measures. Sleep interventions reduced daily energy intake by 147.5 calories per day across five studies with 223 participants, and by 238 calories per day in three studies involving 122 participants with overweight or obesity. The review also reported lower sugar intake and higher protein intake, while finding no significant effects on physical activity, sedentary behavior, waist circumference or body composition outcomes. (onlinelibrary.wiley.com) Participants in the included studies had a mean age of 54.3 years and a mean BMI of 26.6, according to the summary of the analysis. Sleep outcomes also improved, with sleep duration increasing by 40.9 minutes, time in bed by 62.9 minutes, Pittsburgh Sleep Quality Index scores falling by 1.47 points and Insomnia Severity Index scores falling by 3.02 points. (onlinelibrary.wiley.com) A separate 2025 meta-analysis by many of the same Birmingham-based researchers reported that CBT-I and sleep hygiene interventions reduced HbA1c by 0.27 percentage points overall and by 0.43 percentage points compared with controls in people with type 2 diabetes. That paper concluded that addressing sleep insufficiency should be part of diabetes care, providing related context for the adiposity findings in patients with metabolic disease. (sleepwakeadvisor.com) The American Diabetes Association’s 2026 Standards of Care say obesity management is highly beneficial in treating type 2 diabetes and that modest weight loss improves glycemia and can reduce the need for glucose-lowering medications. The new sleep-intervention review adds evidence on a behavioral approach that may sit alongside established counseling, pharmacologic treatment and metabolic surgery, though the review itself reported mixed results across intervention types and did not show significant benefits for sleep extension alone. (journals.sagepub.com) The review’s searches ran through April 2025, and the article was received on June 10, 2025, revised on March 28, 2026 and accepted on March 31, 2026. The findings are available in *Obesity Reviews* under the title “The Effect of Behavioral Sleep Interventions on Measures of Obesity, Dietary Intake and Physical Activity in Adults With Poor Sleep Health.” (onlinelibrary.wiley.com) (diabetesjournals.org)