Wearable biosensors represent an advanced solution for physiological and metabolic monitoring under extreme operational conditions. This review aimed to comparatively analyze the functionality, technological characteristics, and applicability of wearable biosensors used for nutritional and physiological monitoring in military and high-performance contexts. A total of 26 scientific articles (2015–2025) indexed in the Web of Science – Core Collection were included based on defined eligibility criteria. Data extraction focused on monitored parameters, transduction technologies, biosensor type, application context, and study design. Each device was assessed using a functional scoring system evaluating portability, accuracy, and operational utility. The results revealed high average scores for portability and field applicability, especially among electrophysiological and optical biosensors. However, most devices focused on cardiovascular, respiratory, and thermoregulatory monitoring, with limited integration of nutrition-specific biomarkers such as glucose, lactate, or salivary analytes. Only a few systems provided truly multimodal tracking. These findings emphasize a significant technological gap in the integration of comprehensive metabolic monitoring within wearable platforms. The analysis also highlights critical innovation priorities: development of autonomous, multisensory biosensors; enhanced energy autonomy; and increased data fusion capacity. In conclusion, wearable biosensors offer promising tools for strengthening physiological resilience, supporting preventive strategies, and improving real-time decision-making in military theaters. However, further innovation is needed to achieve robust, field-ready systems capable of holistic physiological and nutritional surveillance.