Ultra-Processed Food, Reward System and Childhood Obesity

Abstract

Obesity and overweight are a major public health problem globally. Diet quality is critical for proper child development, and an unhealthy diet is a preventable risk factor for noncommunicable diseases (NCDs), such as obesity. Consumption of sugar-sweetened beverages and ultra-processed foods (UPFs) in childhood may increase the BMI/BMI z-score, body fat percentage, or likelihood of overweight. A strict feeding regulation system allows for sufficient food to be consumed to meet ongoing metabolic demands while avoiding overconsumption. This narrative review explores the issues of obesity and the regulation of food intake related to reward systems and UPF consumption. Nutrient composition alone cannot explain the influence of UPFs on the risk of obesity. Furthermore, the non-nutritional properties of UPFs may explain the mechanisms underlying the relationship with obesity and NCDs. UPFs are designed to be highly palatable, appealing, and energy dense with a unique combination of the main taste enhancer ingredients to generate a strong rewarding stimulus and influence the circuits related to feeding facilitation. How individual UPF ingredients influence eating behavior and reward processes remains not fully elucidated. To increase the knowledge on the relationship between UPFs and pediatric obesity, it may be useful to limit the rapid growth in the prevalence of obesity and subsequent related complications, and to develop new strategies for appropriate food and nutrition policies.

Keywords: adolescents; brain reward system; children; feeding regulation; nutrients intake; obesity; ultra-processed food; unhealthy dietary pattern.

Figure 1

Graphical representation showing the process of the paper selection and exclusion used in writing this narrative review.

Figure 2

Graphical representation of the reward system. In the reward system, subcortical structures, prefrontal cortex, brainstem, and hypothalamic circuity are involved.

Figure 3

Graphical representation of the reward-behavior cycle. The reward system is activated by external or internal stimuli. The effects of the reward system activation involves several physiological processes: pleasure, wish, and learning, leading to a reward-behavior cycle with an escalation in the consumption of those unhealthy foods.

Figure 4

Schematic representation of nutritional and non-nutritional characteristics of ultra-processed foods compared to unprocessed or minimally processed foods. Exceptions to the statements made are indicated with an asterisk, respectively: * for light-soft drinks, ** for sodium.

Figure 5

Schematic graphical representation of potential interventions applicable to counter the global overconsumption of UPFs, with a focus on the child population.