## 1 Introduction
These levels depend on the cocoa content, which is typically between 50% and 90% in dark chocolate, whereas white chocolate is completely devoid of these bioactive compounds, as it only contains cocoa butter [13; 14; 15]. Cocoa and dark chocolate have been associated with several physiological effects, including vasodilation, enhanced oxygen and glucose delivery, improved cognitive function, anti-inflammatory and antioxidant activity, muscle pain reduction, and mood improvement [16; 17; 18; 19]. Importantly, the bioactive compounds in dark chocolate appear to mitigate the negative effects of inflammatory processes induced by exercise, particularly high-intensity exercise. This is achieved by reducing oxidative stress and systemic inflammation, which are key contributors to post-exercise recovery challenges [20]. Although some studies have reported inconsistent findings regarding the efficacy of cocoa flavonoids in reducing inflammatory markers, there is evidence to support potential benefits in specific contexts. For example, dark chocolate rich in flavonoids has been associated with reduced levels of inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6), likely through mechanisms involving modulation of the gut microbiota and improved endothelial function [21; 22]. These effects are particularly evident when high concentrations of cocoa are consumed and in clinical populations such as individuals with obesity or diabetes [16; 17; 18; 19; 20; 23; 24]. These findings emphasize the necessity of investigating the potential effects of dark chocolate on sports performance. The bioactive compounds of dark chocolate may confer synergistic benefits, potentially enhancing recovery and reducing exercise-induced inflammation. However, the variability in bioactive compound concentrations across chocolate products and the necessity for dose-specific investigations must be considered when interpreting these results [25,26]. In contrast with earlier claims, some studies have reported no significant effects of dark chocolate consumption on IL-6 levels or leukocyte count. This suggests that dosage, duration, and population characteristics may play a critical role in determining outcomes [27]. Other investigations have explored the impact of dark chocolate on perceived muscle pain and functional recovery. However, results remain inconclusive, particularly among professional athletes and well-trained individuals [28]. To explore the possible effects of cocoa flavonols (CF), the main class of polyphenols present in cocoa, and exercise performance, [PERSON] and [PERSON] conducted a study in which they measured performance using a maximum distance time sprint test, completed after 20 min of cycling. They observed that consuming 259 mg of CF daily for 14 days resulted in covering 17% longer distance than at baseline and 13% longer distance than when consuming a white chocolate control. The distance covered during Yo-Yo IRT1 increased after CF supplementation (616 mg CF for 7 days) compared to baseline, while the placebo group covered 5.8% less distance. The mechanism behind this effect could be attributed to CF's ability to decrease ROS production and attenuate fatigue. This suggests that CF may have reduced the potential oxidative stress associated with training, thus delaying fatigue [29]. Given this evidence, this pilot study aimed to evaluate the acute effects of dark chocolate consumption on wellness scores, perception of effort, and GPS-based performance measures in young elite soccer players during a 4-week intervention period. We hypothesized that well-being scores and GPS-based performance measures would improve with DC use and that perception of effort would decrease compared to the control condition.