Combined use of a wristband and a smartphone to reduce body weight in obese children: randomized controlled trial C. Mameli 1 , D. Brunetti 1 , V. Colombo 1 , G. Bedogni 2 , L. Schneider 3 , F. Penagini 1 , B. Borsani 1 and G. V. Zuccotti 1 1 Department of Pediatrics, Children’s Hospital Vittore Buzzi, University of Milan, Milan, Italy; 2 Clinical Epidemiology Unit, Liver Research Center, Basovizza, Trieste, Italy; 3 Department of Pediatrics, Luigi Sacco Hospital, Milan, Italy Address for correspondence: Professor GV Zuccotti, Department of Pediatrics, Children’s Hospital Vittore Buzzi, University of Milan, Via Castelvetro 32, 20154 Milan, Italy. E-mail: gianvincenzo.zuccotti@unimi.it Received 12 November 2015; revised 10 September 2016; accepted 17 October 2016 Summary Background: Technological instruments may help control paediatric obesity. Objective: We tested whether a personalized programme based on the energy expenditure obtained from a wristband (WB) and the energy intake obtained from a smartphone application (APP) is superior to a standard approach at promoting weight loss. Methods: We performed a randomized controlled trial in obese children aged 10–17 years. The experimental (EXP) and control (CTR) groups were given a low-energy diet and a prescription for physical activity. The EXP group was equipped with a WB and an APP and given personalized feedback every 7 days. The main outcome was weight loss at 3 months. Results: The mean (standard deviation) z-score of body mass index at the enroll- ment was 2.20 (0.47) in the EXP (n = 16 out of 23) and 2.09 (0.34) in the CTR group (n = 14 out of 20) of children who completed the trial. The mean (95%CI) difference in weight loss at 3 months was 0.07 kg (95%CI: 2.81 to 2.96) for EXP vs. the CTR. Conclusion: A personalized lifestyle programme based on a WB and an APP was not superior to a standard lifestyle programme at promoting weight loss in obese children. Keywords: children, obesity, remote sensing technology, smartphone. Introduction The prevalence of paediatric obesity is rapidly increasing (1). Both low-energy expenditure (EE) and high-energy intake (EI) are contributing to this phenomenon (2). However, obesity is much more than a positive energy balance, because it has important genetic, psychological, behavioural and environmental roots (2). Randomized controlled trials (RCT) have shown that obese children may lose weight by lifestyle interven- tions (3). However, the results obtained in the real-life setting are largely unsatisfactory (4). Most children own smartphones and prefer to learn using electronic media (5). Such instruments may help children control obesity. Specific smartphone applications (APP) and short messaging services (SMS) may be useful to promote healthy eating and physical activity (PA) (6). Besides the intrinsic interest of children for electronic gadgets, the possibility of obtaining frequent feedback makes these instruments potential means for promot- ing weight loss (7). APP and SMS have been shown to be able to induce short-term behavioural changes in adults (8,9). However, the effectiveness of mobile health technology (m-health) to promote weight loss is equivocal in children (10–13). APP-based tracking of food consumption has been associated with positive changes in the dietary behaviour of obese children (14). A recent review reported increases of PA and self-monitoring in the absence of relevant changes of body mass index (BMI) (10). Importantly, PA was always self-reported, posing a problem of measurement validity. Accelerometers allow an objective assessment of PA and are the most practical means for evaluating EE (15). We decided to objectively assess PA-incorporating accelerometers in an m-health technology weight loss programme designed for obese children. ORIGINALRESEARCH doi:10.1111/ijpo.12201 © 2016 World Obesity Federation Pediatric Obesity ORIGINALRESEARCH