Let's Not Just Dismiss the Weight Watchers Kurbo App

This month, Weight Watchers (WW) launched Kurbo, a free nutrition and weight loss app for children ages 8 to 17. The app was originally developed at Stanford University using a “traffic light system” for food choices. To promote lifestyle changes and help children achieve a healthier weight, WW added breathing exercises, a Snapchat-inspired interface, and the ability for children and parents to log their health-related goals. Weekly video coaching is also available for a fee. Since its release, there has been considerable attention to potential adverse effects of use of the app and calls to abandon weight management efforts for children altogether.¹ As clinicians and scientists who study and care for children and families with overweight or obesity and its associated chronic diseases, we are concerned about the message this sends. While extra precautions are especially warranted and justified for any program targeted and directly marketed to children, it is important to not just completely dismiss new and promising approaches to prevention and treatment and to understand the underlying science.

One of the central components of the app involves the adoption of the “traffic light system” diet in which foods are categorized into the colors of a traffic light signal based on their caloric and nutritional content. Intake recommendations are made based on the colors with limits suggested for “red category foods,” while “green category foods” can be eaten freely. The traffic light diet was developed by Epstein and Squires (1988)² and first published in the 1980s. It was part of an eight-week program for children ages 1 to 12 years and their parents to begin a lifetime of good eating habits, health, and weight loss.² The traffic light system allows for children and families to track how many green, yellow, and red foods they eat in a day or week. It has since been used by a variety of obesity scientists in multiple clinical trials to improve eating behaviors and weight status of children.^3,4 It was given a grade of “1”which is the highest level of evidence in the Academy of Nutrition and Dietetics Evidence Analysis Library, with “good or strong evidence” to support the statement that the Traffic Light Diet is an effective way of managing energy and food intake in children.⁵ The benefits of a traffic light system appear to be sustained long term, with modest, sustained weight loss up to 10 years following the intervention.⁶

The Traffic Light Diet has been primarily used with non-Hispanic white, higher socioeconomic status families with children ages 6–12 years.^3,7 Thus, the generalizability of the diet's effects among racial/ethnic minorities or low socioeconomic status families and youth, and other ages, remains understudied. Additionally, the Traffic Light Diet was designed to be part of a larger “package” of interventions that generally include family involvement and interaction with clinical providers. Thus, while there is strong scientific rationale for the use of the Traffic Light Diet in the Kurbo app, questions remain about the effects of the diet as a stand-alone component directed at children outside the context of a clinical program and without the supervision of a health professional.

The significant and important concern that many have raised about obesity treatment programs has been the potential risk for putting too great an emphasis on weight loss which may lead to disordered eating, depression, low self-esteem, or poor body image. Despite being relatively uncommon.⁸ eating disorders carry one of the highest mortality risks of any psychiatric disorder.⁹ Therefore, the potential risk for eating disorder development is a fair and necessary concern. However, obesity treatment programs must consider the balance between the harms of excess weight and those that may occur from weight management.

Obesity occurs in approximately 17% of youth aged 2 to 19 years,¹⁰ and in up to ∼23% of youth from families of lower socioeconomic status.¹⁰ Obesity is also associated with serious comorbidities, including cardiometabolic disease, depression, and some types of cancers.¹¹ Despite the concerns for eating disorder, a recent systematic review and meta-analysis demonstrated that face-to-face pediatric weight management interventions, with a dietary component, actually decreased eating disorder prevalence and risk.¹² Thus, it would be unethical and irresponsible to not offer weight management or support to a child with severe obesity, prediabetes, abnormal liver function studies, or high blood pressure as has been suggested.

As clinicians and scientists, we aim to do no harm. So where does the Kurbo app fall in this spectrum from salvation to damnation? The basis of the app (the traffic light system) is evidence-based but only in the context of supervision by clinical providers. Mounting evidence suggests that obesity prevention and management interventions that included health coaching delivered by community health workers, health coaches, or promotoras are effective.¹³ Thus, well-trained coaches may be an effective resource to pair with the Kurbo app, but the training or certification the Kurbo coaches receive is unclear. This raises concerns about their potential to effectively communicate with children and families around the sensitive topic of weight. Additionally, the Kurbo traffic light system differs from that developed by Epstein and Squires² and Epstein et al.¹⁴ It excessively focuses on calories rather than the quality of those calories. For example, it ranks healthful foods that many children eat, as “red foods” including peanut butter, nuts, hummus, 2% and whole milk. Since children may infer the quality of the foods based on this traffic light system, the classification of these foods as “red foods” may be harmful for their understanding of nutritional principles. Other shortcomings of Kurbo include the images of children with their weight loss amounts on the website and the focus on weight loss in advertisements, rather than on development of healthy lifestyle behaviors. More data are needed to understand the effects of the app alone and the changes made to the original traffic light system.

In an ideal world, children with overweight or obesity would have access to an intensive, multicomponent behavioral intervention with a team of pediatric obesity medicine doctors, registered dietitians, psychologists, exercise physiologists, and/or social workers to address their needs.¹⁵ However, this is not currently possible for many, as most people don't have access via their health insurance and cannot afford to even see a registered dietitian, let alone this entire team. If Kurbo works, it could be a paradigm shift in how individuals, particularly those of lower socioeconomic status, can access pediatric obesity care. Yet, we also want to be careful to avoid unintended consequences.

Kurbo has sparked important and productive conversation about the need for easily disseminated and sustainable strategies to prevent and treat childhood obesity. It has also raised questions for additional research regarding the role of apps, health coaches, and the need for parental involvement in improving health-related behaviors and obesity. Overall, we are cautiously hopeful that this could be part of the piece of the puzzle to improving health in youth.