Nutritionally adequate and environmentally respectful diets are possible for different diet groups: an optimized study from the NutriNet-Santé cohort.

BACKGROUND: Research has shown that vegetarian diets have a low environmental impact, but few studies have examined the environmental impacts and nutritional adequacy of these diets together, even though vegetarian diets can lead to nutritional issues. OBJECTIVES: Our objective was to optimize and compare 6 types of diets with varying degrees of plant foods (lacto-, ovolacto-, and pescovegetarian diets and diets with low, medium, and high meat content) under nutritional constraints. METHODS: Consumption data in 30,000 participants were derived from the French NutriNet-Santé cohort using an FFQ. Diets were optimized by a nonlinear algorithm minimizing the diet deviation while meeting multiple constraints at both the individual and population levels: nonincrease of the cost and environmental impacts (as partial ReCiPe accounting for greenhouse gas emissions, cumulative energy demand, and land occupation, distinguishing production methods: organic and conventional), under epidemiologic, nutritional (based on nutrient reference values), and acceptability (according to the diet type) constraints. RESULTS: Optimized diets were successfully identified for each diet type, except that it was impossible to meet the EPA (20:5n-3) + DHA (22:6n-3) requirements in lacto- and ovolactovegetarians. In all cases, meat consumption was redistributed or reduced and the consumption of legumes (including soy-based products), whole grains, and vegetables were increased, whereas some food groups, such as potatoes, fruit juices, and alcoholic beverages, were entirely removed from the diets. The lower environmental impacts (as well as individual indicators) observed for vegetarians could be attained even when nutritional references were reached except for long-chain n-3 (omega-3) fatty acids. CONCLUSIONS: A low-meat diet could be considered as a target for the general population in the context of sustainable transitions, although all diets tested can be overall nutritionally adequate (except for n-3 fatty acids) when planned appropriately.This trial was registered at clinicaltrials.gov as NCT03335644.

Household preferences for reducing greenhouse gas emissions in four European high-income countries: Does health information matter? A mixed-methods study protocol.

BACKGROUND: It is now universally acknowledged that climate change constitutes a major threat to human health. At the same time, some of the measures to reduce greenhouse gas emissions, so-called climate change mitigation measures, have significant health co-benefits (e.g., walking or cycling more; eating less meat). The goal of limiting global warming to 1,5° Celsius set by the Conference of the Parties to the United Nations Framework Convention on Climate Change in Paris in 2015 can only be reached if all stakeholders, including households, take actions to mitigate climate change. Results on whether framing mitigation measures in terms of their health co-benefits increases the likelihood of their implementation are inconsistent. The present study protocol describes the transdisciplinary project HOPE (HOuseholds' Preferences for reducing greenhouse gas emissions in four European high-income countries) that investigates the role of health co-benefits in households' decision making on climate change mitigation measures in urban households in France, Germany, Norway and Sweden. METHODS: HOPE employs a mixed-methods approach combining status-quo carbon footprint assessments, simulations of the reduction of households' carbon footprints, and qualitative in-depth interviews with a subgroup of households. Furthermore, a policy analysis of current household oriented climate policies is conducted. In the simulation of the reduction of households' carbon footprints, half of the households are provided with information on health co-benefits of climate change mitigation measures, the other half is not. Households' willingness to implement the measures is assessed and compared in between-group analyses of variance. DISCUSSION: This is one of the first comprehensive mixed-methods approaches to investigate which mitigation measures households are most willing to implement in order to reach the 1,5° target set by the Paris Agreement, and whether health co-benefits can serve as a motivator for households to implement these measures. The comparison of the empirical data with current climate policies will provide knowledge for tailoring effective climate change mitigation and health policies.

Role of friction in the mechanics of nonbonded fibrous materials.

Discrete element simulations are employed to study the influence of static friction on the mechanical response of assemblies of nonbonded semiflexible fibers during cycles of isostatic compressions and releases. Hysteresis is evidenced during the cycles and is related to the sensitivity of the frictional contacts on normal forces. Nonzero frictions are shown to decrease both the packing density and caging number but do not affect the critical exponents that characterize the pressure and bulk and shear moduli. Assemblies of frictionless fibers are found fragile in the sense that they resist isostatic compressions but have a zero shear modulus at all densities.