Keep it CooL! Results of a two-year CooL-intervention: a descriptive case series study.

BackgroundCoaching on Lifestyle (CooL) is a two-year healthcare intervention for people with overweight or obesity, stimulating weight reduction by promoting sustained healthier behavior. The objective of this study is to investigate the effects of CooL on participants anthropometrics, personal factors and behavioral factors over the two-year timeframe of CooL. MethodsA descriptive case series study, using a broad set of routinely collected data on anthropometrics, personal factors and behavioral factors of adults living across the Netherlands. The data were collected between November 2018 and December 2021 among participants of CooL (N=746) at three moments during the intervention: at baseline (T0), at 8 months (T1) after completion of phase 1 and at 24 months (T2) after ending CooL. Changes over time were analyzed using paired t-tests comparing baseline to T1 and baseline to T2. In addition, potential differences on outcomes in subgroups based on education level, weight status and group size were examined using paired t-tests and ANOVA-tests. ResultsThe results showed changes in the desired direction on all outcomes at 24 months compared to baseline. The largest effects were seen on perceived health, attentiveness towards meal size and meal composition (large effect size). Mean weight loss was 4.13 kilograms (SD 7.54), and mean waist circumference decreased with 4.37 centimeters (SD 8.59), indicating a medium to large effect size. Changes in outcomes were similar across all subgroups consisting of participants with different educational level, BMI at baseline and in different group sizes. ConclusionThe study showed sustained effects in weight-related outcomes of CooL over the timeframe of 24 months supporting the two-year set-up of CooL. The outcomes indicate that CooL is appropriate and effective for different group sizes and for a wide variety of participants irrespective of gender, age, BMI at baseline or level of education.