Ecological Validation of Labeled Protein Content Differences in Commercial Brown Sugar Using Invertebrate Fitness

Background/Objectives: Nutritional labels, often based solely on chemical analysis, may not fully represent a food’s in vivo biological value. This study aimed to determine if differences in protein content declared on commercial brown sugar labels translate into functional nutritional differences, evaluated using nutritional ecology assays. We hypothesized that higher labeled protein content would correspond to superior biological performance in consumer organisms. Methods: Commercial brown sugars were categorized as high-protein (HPBS) or low-protein (LPBS) based specifically on their nutritional label information. Using Drosophila melanogaster (fruit flies) and Pardosa pseudoannulata (wolf spiders) as models, we compared the effects of diets/solutions containing HPBS, LPBS, or a control. Measured outcomes included Drosophila total developmental time, cumulative fecundity (F1-F3 generations), and climbing ability (negative geotaxis), and Pardosa survival duration under starvation conditions. Results: Spiders provided with the HPBS solution exhibited significantly longer survival than those given LPBS or water. While Drosophila developmental time did not differ significantly between HPBS and LPBS groups, flies reared on the HPBS diet showed significantly higher cumulative fecundity and superior climbing ability compared to both the LPBS and control groups. Conclusions: Brown sugars labeled with higher protein content provide demonstrably greater biological benefits in invertebrate models, particularly impacting survival, fecundity, and physical performance. These findings validate the physiological relevance of this specific label information and highlight the value of integrating label data with functional ecological assays for a more comprehensive assessment of food quality beyond chemical composition alone.