Diet-related greenhouse gas emissions assessed by a food frequency questionnaire and validated using 7-day weighed food records

Abstract

BackgroundThe current food system generates about 25 % of total greenhouse gas emissions (GHGE), including deforestation, and thereby substantially contributes to the warming of the earth’s surface. To understand the association between food and nutrient intake and GHGE, we therefore need valid methods to assess diet-related GHGE in observational studies.MethodsLife cycle assessment (LCA) studies assess the environmental impact of different food items. We linked LCA data expressed as kg carbon dioxide equivalents (CO2e) per kg food product to data on food intake assessed by the food frequency questionnaire (FFQ) Meal-Q and validated it against a 7-day weighed food record (WFR). 166 male and female volunteers aged 20–63 years completed Meal-Q and the WFR, and their food intake was linked to LCA data.ResultsThe mean GHGE assessed with Meal-Q was 3.76 kg CO2e per day and person, whereas it was 5.04 kg CO2e using the WFR. The energy-adjusted and deattenuated Pearson and Spearman correlation coefficients were 0.68 and 0.70, respectively. Moreover, compared to the WFR, Meal-Q provided a good ranking ability, with 90 % of the participants classified into the same or adjacent quartile according to their daily average CO2e. The Bland-Altman plot showed an acceptable level of agreement between the two methods and the reproducibility of Meal-Q was high.ConclusionsThis is the first study validating the assessment of diet-related GHGE by a questionnaire. The results suggest that Meal-Q is a useful tool for studying the link between food habits and CO2e in future epidemiological studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-016-0110-7) contains supplementary material, which is available to authorized users.

Is a diet low in greenhouse gas emissions a nutritious diet? – Analyses of self-selected diets in the LifeGene study

“…We identified published LCA data for 65 food items and food groups representative of typical food consumption in Sweden described in detailed elsewhere and about half of the LCA data came from the same source [21]. These 65 food items and groups matched the food items/questions in Meal-Q, for example, we asked for 3 kinds of bread in Meal-Q (white, whole grain and crisp, respectively), but applied the same LCA data for all 3 kinds of bread.…”

“…The GHGE include emissions from agriculture and its inputs, food processing, distribution and retailing [21]. If LCA studies did not include emissions from distribution and retailing, emission were imputed by adding emissions linked to retail, transportation and packaging using Swedish data [21].…”

“…If LCA studies did not include emissions from distribution and retailing, emission were imputed by adding emissions linked to retail, transportation and packaging using Swedish data [21]. Emissions after the retail phase were not included, such as transports to the household, storing and cooking, as well as from waste management.…”

“…cooking of rice, and dehydration, i.e. cooking of meat [21]. In addition, we adjusted for unavoidable food losses (i.e.…”

Adherence to dietary recommendations for Swedish adults across categories of greenhouse gas emissions from food

“…The proportion of adherence to nutrition recommendations may be an important indicator of the public health effect of food habits with low and high GHGE. In our previous study, using a validated FFQ (11,25) , we compared the micronutrient intakes with RI, using goals for menu planning expressed as nutrients/MJ for ages 6-65 years. However, RI should preferably be used when planning diets for groups and the requirements are lower for almost all individuals.…”