Nutrient-sensitive approach for sustainability assessment of different dietary patterns in Australia.

Background: Understanding the relation between sustainability and nutrients is important in devising healthy and sustainable diets. However, there are no prevailing methodologies to assess sustainability at the nutrient level.

Objectives: The aim was to examine and demonstrate the potential of integrating input-output analysis with nutritional geometry to link environmental, economic, and health associations of dietary scenarios in Australia with macronutrients.

Methods: One-day dietary recalls of 9341 adult respondents (age ≥18 y) of the latest available cross-sectional National Nutrition and Physical Activity Survey-2011/12 of Australia were integrated with the input-output data obtained from the Australian Industrial Ecology Virtual Laboratory to calculate the environmental and economic impacts of dietary intakes in Australia. Australian adults' dietary intakes were classified into 3 dietary scenarios: "vegan," "pescatarian," and "omnivorous." Then, the relations between nutritional, economic, and environmental characteristics of the 3 dietary scenarios were demonstrated with the diets' macronutrient composition in a multidimensional nutritional geometry representation to link the sustainability indicators with macronutrients.

Results: Nutrient density and economic and environmental indicators increased as the percentage of energy from proteins increased and decreased as the percentage of energy from fats increased for the 3 dietary scenarios, except for the nutrient density and water use of the "vegan" dietary scenario. Energy density increased as the percentage of energy from fats increased and decreased as the percentage of energy from proteins increased for "pescatarian" and "omnivorous" dietary scenarios. In the "vegan" dietary scenario, nutrient density and water use increased as the percentage of energy from proteins increased; however, these decreased as the percentage of energy from carbohydrates increased, instead of fats.

Conclusions: The study presents a new approach to analyzing the relations between sustainability indicators, foods, and macronutrients and establishes that proteins, irrespective of the source of protein, are driving dietary environmental and economic impacts.