The relationship between dietary greenhouse gas emissions and demographic characteristics in high-income countries

The food we eat has a critical impact on human and planetary health. Food systems are responsible for approximately a third of total global greenhouse gas emissions (GHGE). This review summarises studies that have measured dietary GHGE and assessed their associations with various demographic variables. Most studies report dietary emissions at the individual level, but some studies use households as the unit of analysis. Studies investigating individuals estimate dietary intakes using 24-hour dietary recalls, FFQ, diet history interviews, food diaries or other dietary records. Studies investigating households rely on food purchasing data and expenditure surveys. The majority of studies estimate dietary GHGE using process-based life cycle assessments. It is difficult to directly compare emissions estimates between studies at either the individual or household-level due to methodological differences. In general, there are mixed findings with regard to the relationships between various demographic variables and dietary emissions, although older adults generally had higher dietary GHGE than younger adults, and men typically had higher dietary GHGE than women, even when standardising for total energy intake. This review may be useful in informing and targeting policies and interventions to reduce GHGE of dietary intake.