Proto-evidence-based therapeutic nutrition: rediscovering Georges Dujardin-Beaumetz's 19th-century insights for modern clinical nutrition.

Nutrition science continues to face periods of epistemic uncertainty, particularly when reductionist models fail to explain complex interactions between diet, lifestyle, and chronic disease. This narrative review aims to demonstrate how Georges Dujardin-Beaumetz in his work L'Hygiène alimentaire (1887) anticipates key concepts of modern clinical nutrition and evidence-based medicine, and to identify the conceptual continuities between 19th-century clinical thought and contemporary nutrition therapy. We analyzed how Dujardin-Beaumetz systematically framed nutrition as a therapeutic intervention, grounded in physiological reasoning and careful clinical observation. His approach anticipates many principles central to contemporary medical nutrition therapy: individualized dietary planning, integration of nutrition with systemic physiology, moderation in food intake, and the use of diet to influence metabolism, immune competence, and chronic disease risk. He emphasized protein metabolism, nitrogen balance, the pathological effects of overnutrition, and the modulation of gastrointestinal and metabolic diseases through diet. While lacking modern biochemical knowledge or formal trial methodology, his work embodies proto-evidence-based principles: observation, cause-and-effect reasoning, critical evaluation of interventions, and adjustment based on patient response. Revisiting L'Hygiène alimentaire highlights a conceptual continuity between 19th-century clinical reasoning and twenty-first-century practice. Understanding these early insights provides both historical context and practical guidance for modern clinicians, reinforcing the importance of integrative, physiologically informed, and patient-centered approaches to nutrition therapy.