With the growing interest in sports nutrition and its impact on athletic performance, understanding the specific needs of adolescent athletes, particularly females, is crucial for optimizing their training and performance outcomes. The three variants of the Protein-rich bar (PB1, PB2, PB3) with the CB were developed by using different ingredients. The research employs a mixed-methods approach, combining nutritional analysis of developed bars with performance assessments among adolescent swimmers’ girls. Firstly, organoleptic evaluation (9-point hedonic scale) was performed on the variants of Protein-rich bar with the CB. Then nutritional analysis involves proximate (moisture, ash, protein, crude fat, crude fiber, CHO), mineral (calcium, iron), as well as antioxidant analysis (DPPH, TPC, vitamin C) assessed on selected variants of Protein-rich bar with the CB. Pre- and post-intervention were done on two groups for 3 months and performance assessments included anthropometric measurement, sit and reach test, hand grip strength test, Nelson hand reaction time test, and Tuttle pulse ratio test. Preliminary findings suggested that the developed bars (PB1) provide a more balanced nutritional profile than the CB. Moisture 10.2±0.66%, ash 3.7±0.27%, protein 22.3±0.74 g, crude fat 13.1±0.41 g, crude fiber 11.5±0.02 g, CHO 39.4±0.19 g, iron 4.4±0.15 mg, calcium 82.4±0.21 mg, DPPH 47.6±0.31%, TPC 53.1±0.11 mg GAE, and vitamin C 11.2±0.19 mg in 100 g respectively in PB1 and significantly difference at (p<0.05). Additionally, the consumption of PB1 bar appears to positively impact higher work performance among adolescent swimmers girls. Overall, this study contributes to the growing body of research on sports nutrition tailored to adolescent athletes, particularly focusing on the nutritional needs of swimmers girls.