Effect of a Cognitive Behavioural Therapy Intervention to Improve Sleep on Food Preferences: A Randomized Controlled Trial in Adults with Overweight and Obesity.

Short sleep duration and poor sleep quality are associated with higher energy intake and increased preference for sweet foods. The aim was to determine whether cognitive behaviour therapy for insomnia (CBTi) i) improved sleep duration and quality and ii) altered dietary behaviours and food preferences. Participants (sleep duration <7 h; Pittsburgh Sleep Quality Index (PSQI) > 5; BMI ≥25 kg m-2) were randomised to 8 weeks of CBTi (n = 14) or Control (n = 13). Sleep characteristics, dietary intake (3-day food diaries), food cravings (Control of Eating Questionnaire), and explicit liking, explicit wanting, and implicit wanting of foods (Leeds Food Preference Questionnaire) were assessed pre- and post-intervention. Self-reported sleep duration increased by 49.2 min more in the CBTi intervention compared with the Control group (+1.11 ± 0.21 h vs +0.29 ± 0.30 h, p = 0.01), self-reported sleep quality (PSQI) improved more (-5.86 ± 0.73 vs -0.62 ± 0.92, p = 0.00002), and daytime sleepiness (Epworth Sleepiness Scale) decreased more (-2.64 ± 0.80 vs +1.54 ± 0.66, p = 0.00004) in the Intervention group. However, there were no differences accelerometer-measured sleep duration and sleep efficiency between groups. The Intervention group had greater increases in food craving control (+21.9 ± 4.7 mm vs -3.0 ± 4.3 mm, p = 0.002), and greater reductions in craving for sweet (-16.4 ± 6.0 mm vs +3.3 ± 4.2 mm, p = 0.01) and savoury (-15.0 ± 3.0 mm vs +0.8 ± 4.8 mm, p = 0.003) foods. Implicit wanting of low-fat savoury foods increased (+12.3 ± 3.2 vs -2.1 ± 3.1, p = 0.006) and implicit wanting of high-fat sweet foods decreased (-15.8 ± 7.4 vs +9.8 ± 4.4, p = 0.001) more in the Intervention group. There was substantial under-reporting of dietary intake with 19 participants reporting energy intake <1.1 x basal metabolic rate. Amongst those with valid dietary measures, there were no significant differences in changes in energy or macronutrient intake between groups, but statistical power to detect effects was limited. In conclusion, this study demonstrates that a CBTi intervention leads to improvements in food craving control and changes in food preference. Future research is needed to determine whether this translates into differences in dietary intake.