Health Outcomes and Sustainable Dietary Patterns
The Question
What are the health outcomes of following sustainable dietary patterns?The Recommendation
Data from modelling studies suggests that dietary changes towards sustainable dietary patterns (predominantly plant-based diets that meet energy needs) are associated with health benefits related to reduced mortality and chronic disease risk. The health and environmental impacts are particularly noted in high income countries. It is acknowledged that context-specific recommendations are needed to address environmental impacts in different regions (e.g. nutritional benefits derived from raising livestock in otherwise non-arable land).
The Evidence
A 2016 systematic review identified that switching from usual population level diets (i.e. typical Western diet) to alternative sustainable dietary patterns (e.g. vegan, vegetarian, reducing and replacing animal with plant-based foods, pescatarian and Mediterranean) was associated with reduced all-cause mortality rate (<1 to 19%), reduced coronary heart disease risk (6 to 10%), reduced diabetes risk (7 to 12%) and reduced colorectal cancer risk (7 to 12%). There was no association between the magnitude of environmental benefits and health benefits.
A 2018 modelling analysis examining the impact of sustainable dietary patterns on chronic disease in 158 countries identified that energy-balanced dietary patterns (i.e. flexitarian, pescatarian, vegetarian and vegan) were associated with 19 to 22% reduced mortality, particularly in high income countries where baseline diets were most imbalanced (i.e. excess energy intake, low in vegetables/fruit and high in red/processed meat).
Remarks
In the included studies, baseline diets were obtained from average population-level intakes or food waste data and compared to theoretical alternative sustainable dietary patterns by modelling diets. The review authors described various dietary patterns that comprised ‘sustainable diets’ from exclusively plant-based to diets containing small amounts of animal-source foods; therefore, this term was retained rather than referring to plant-based diets alone. The health benefits from sustainable diets were attributed to increases in fruit, vegetable and plant-based protein consumption, reductions in red and processed meat and lower overall energy intake.
See Additional Content: What dietary patterns are associated with environmental benefits (e.g. reduced impacts on greenhouse gases, land and water)?
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