**Background:** Food production contributes significantly to global environmental change, and Mongolia has experienced notable climate warming (≥2°C from 1940–2015). The prevalence of obesity in Mongolia (20.9% in men, 26.5% in women) exceeds Asian regional averages (17% and 20%, respectively). The EAT-Lancet Commission's Planetary Health Diet (PHD) provides a framework for diets that support both human health and environmental sustainability, but no prior study had assessed Mongolian diets against this framework. This study aimed to evaluate how Mongolian dietary intake aligns with the PHD, comparing urban vs. rural areas and cold vs. warm seasons, and to compare national dietary recommendations with the PHD.
**Methods:** Dietary intake data were obtained from the Household Socio-Economic Survey (HSES) 2019, a nationally representative survey of 11,197 households (99.7% participation rate). Urban areas included Ulaanbaatar (3,600 households), and rural areas included 20 aimag centers, 306 soum centers, and 891 bags (7,597 households). Dietary intake was assessed using a 30-day dietary record (urban) or 7-day dietary record (rural). Eight food groups were analyzed against PHD health boundaries, with adequacy (%) calculated as dietary intake divided by the PHD boundary intake (converted to the population's actual energy intake of 3,085 kcal/day for whole areas). Analyses were stratified by area (urban: 2,863 kcal/day; rural: 3,529 kcal/day) and season (cold October–March: 3,057 kcal/day; warm April–September: 3,111 kcal/day). The Mongolian Recommended Dietary Intake (RDI) was also compared to the PHD.
**Key Results:** In whole areas, red meat intake was 300 g/day versus the PHD boundary of 17 g/day (range 0–35 g/day), yielding 1,738% adequacy. Vegetable intake was 73 g/day versus 370 g/day (20% adequacy), and fruit intake was 20 g/day versus 247 g/day (8.1% adequacy). Dairy foods (366 g/day, 119% adequacy), tubers (90 g/day, 146% adequacy), saturated oils (16 g/day, 110% adequacy), and added sugars (40 g/day, 105% adequacy) were within or near PHD ranges. Unsaturated oils were low (6.6 g/day, 13% adequacy). Rural areas showed more extreme imbalances than urban areas: red meat adequacy was 1,963% in rural vs. 1,540% in urban; vegetable adequacy was 14% in rural vs. 25% in urban; fruit adequacy was 6.0% in rural vs. 10% in urban. Seasonally, red meat adequacy was higher in cold (1,905%) vs. warm (1,812%) seasons. Other protein sources (chicken, fish, legumes) during both seasons were very low (0.2–15% adequacy), except eggs (86–97% adequacy). The Mongolian RDI also showed high red meat targets (120 g/day, 1,091% adequacy vs. PHD), while vegetable (260 g/day, 113% adequacy) and fruit (200 g/day, 131% adequacy) targets were within PHD ranges.
**Clinical Implications:** The extreme overconsumption of red meat and underconsumption of vegetables and fruits in Mongolia, particularly in rural areas and cold seasons, poses dual risks to population health and environmental sustainability. High animal protein intake is associated with cardiovascular disease and all-cause mortality, while inadequate fruit and vegetable intake increases risks of non-communicable diseases. The findings suggest that limited food diversity due to severe geography, poor food retailer accessibility, and insufficient nutrition education contribute to these dietary patterns. The authors recommend multi-sectoral interventions including improved infrastructure for food access, nutrition education for health professionals and communities, and potential revision of the Mongolian RDI to better align with planetary health goals while respecting cultural feasibility. Limitations include unavailable data on whole grains and some protein sources by area, different survey methods between urban (30-day record) and rural (7-day record) areas, and the lack of direct environmental impact measurements such as GHG emissions.