Current Status of Macronutrient and Energy Intake and Metabolism Among High-Altitude Populations: A Systematic Review

Background/Objectives: Residents of high-altitude regions are chronically exposed to hypoxic and cold environments, which may alter energy metabolism and nutritional requirements, leading to distinct macronutrient intake patterns. However, existing evidence remains fragmented. This systematic review aimed to summarize macronutrient and energy intake among high-altitude populations and compare reported intake levels with dietary reference values to identify potential nutritional risks. Methods: A systematic search of PubMed and Web of Science was conducted for studies published between January 1990 and March 2025. Observational studies reporting dietary intake or dietary patterns among populations living at altitudes of ≥1500 m were eligible. Two reviewers independently screened studies, extracted data, assessed study quality using standardized tools, and synthesized results narratively. Study quality was assessed using the Quality Assessment Tool for Studies with Diverse Designs (QATSDD), with studies scoring ≥60% of the maximum score considered to indicate moderate or higher methodological quality. This review was not registered. Results: A total of 14 studies were included. Energy intake was generally within or close to recommended levels, with suboptimal intake observed in specific regions and population groups. Carbohydrate intake remained high, reflecting grain-based diets, while protein intake usually met or exceeded recommendations. Fat intake showed an increasing trend, particularly among pregnant and lactating women. Several studies reported emerging "modern" dietary patterns characterized by higher consumption of meat, fats, and processed foods, alongside limited dietary diversity. Conclusions: Overall, high-altitude populations exhibit distinctive macronutrient profiles shaped by environmental adaptation and nutritional transition, underscoring the need for altitude-specific dietary guidance and targeted public health interventions.