Welfare and sustainability effects of dietary recommendations

The paper develops a framework combining a model of rational behaviour under dietary constraints, an epidemiological model of diet-related mortality, and a life-cycle-analysis model of environmental impact, which permits the ex-ante assessment of dietary recommendations in multiple sustainability dimensions (i.e., taste cost, welfare effect, deaths avoided, reductions in greenhouse gas emissions and acidification). It is applied to compare in a French context the relative effects and efficiency of six popular sustainable diet recommendations. The results confirm the synergies between the health and environmental dimensions: healthy-eating recommendations usually have a positive effect on the environment, although some exceptions exist. Most of the sustainable diet recommendations appear highly cost-effective, but those most commonly promoted on health grounds (e.g., targeting consumption of salt, fruits and vegetables and saturated fat) rank highest in terms of overall efficiency. Moreover, the valuation of benefits indicates that in most cases health benefits are significantly larger than environmental benefits. Overall, the analysis reveals some under-investment in the promotion of sustainable diet recommendations in France. The general lack of enthusiasm in policy circles for informational measures promoting behavioural change may reflect unrealistic expectations about the speed and magnitude of dietary change rather than an objective assessment of the efficiency of those measures

Economic assessment of nutritional recommendations

The effect of consumers’ compliance with nutritional recommendations is uncertain because of potentially complex substitutions. To lift this uncertainty, we adapt a model of consumer behaviour under rationing to the case of linear nutritional constraints. Dietary adjustments are thus derived from information on consumer preferences, consumption levels, and nutritional contents of foods. A calibration exercise simula tes, for different incomegroups, how the French diet would respond to various nutrition recommendations, and those behavioural adjustments are translated into health outcomes through the DIETRON epidemiological model. This allows for the ex-ante comparison of the efficiency, equity and health effects of ten nutritional recommendations. Although most recommendations impose significant taste costs on consumers,they are highly cost-effective, with the recommen dations targeting salt, saturated fat, and fruits and vegetables (F&V) ranking highest in terms of efficiency. A five percent change in consumption of any of those nutrients or food would reduce premature mortality in excess of 2100 lives annually. By contrast, urging consumers to modify their consumption of fibers, sugar-fat products and dietary cholesterol is unlikely to be socially desirable, often due to large unintended adjustments in some dimensions of dietary quality. Most recommendations are economically progressive, with the exception of that targeting F&

Welfare and sustainability effects of dietary recommendations

The paper develops a framework combining a model of rational behaviour under dietary constraints, an epidemiological model of diet-related mortality, and a life-cycle-analysis model of environmental impact, which permits the ex-ante assessment of dietary recommendations in multiple sustainability dimensions (i.e., taste cost, welfare effect, deaths avoided, reductions in greenhouse gas emissions and acidification). It is applied to compare in a French context the relative effects and efficiency of six popular sustainable diet recommendations. The results confirm the synergies between the health and environmental dimensions: healthy-eating recommendations usually have a positive effect on the environment, although some exceptions exist. Most of the sustainable diet recommendations appear highly cost-effective, but those most commonly promoted on health grounds (e.g., targeting consumption of salt, fruits and vegetables and saturated fat) rank highest in terms of overall efficiency. Moreover, the valuation of benefits indicates that in most cases health benefits are significantly larger than environmental benefits. Overall, the analysis reveals some under-investment in the promotion of sustainable diet recommendations in France. The general lack of enthusiasm in policy circles for informational measures promoting behavioural change may reflect unrealistic expectations about the speed and magnitude of dietary change rather than an objective assessment of the efficiency of those measures

Economic assessment of nutritional recommendations

The effect of consumers’ compliance with nutritional recommendations is uncertain because of potentially complex substitutions. To lift this uncertainty, we adapt a model of consumer behaviour under rationing to the case of linear nutritional constraints. Dietary adjustments are thus derived from information on consumer preferences, consumption levels, and nutritional contents of foods. A calibration exercise simulates, for different income groups, how the French diet would respond to various nutrition recommendations, and those behavioural adjustments are translated into health outcomes through the DIETRON epidemiological model. This allows for the ex-ante comparison of the efficiency, equity and health effects of ten nutritional recommendations. Although most recommendations impose significant taste costs on consumers, they are highly cost-effective, with the recommendations targeting salt, saturated fat, and fruits and vegetables (F&V) ranking highest in terms of efficiency. A five percent change in consumption of any of those nutrients or food would reduce premature mortality in excess of 2100 lives annually. By contrast, urging consumers to modify their consumption of fibers, sugar-fat products and dietary cholesterol is unlikely to be socially desirable, often due to large unintended adjustments in some dimensions of dietary quality. Most recommendations are economically progressive, with the exception of that targeting F&V

Welfare and sustainability effects of dietary recommendations

The paper develops a framework combining a model of rational behaviour under dietary constraints, an epidemiological model of diet-related mortality, and a life-cycle-analysis model of environmental impact, which permits the ex-ante assessment of dietary recommendations in multiple sustainability dimensions (i.e., taste cost, welfare effect, deaths avoided, reductions in greenhouse gas emissions and acidification). It is applied to compare in a French context the relative effects and efficiency of six popular sustainable diet recommendations. The results confirm the synergies between the health and environmental dimensions: healthy-eating recommendations usually have a positive effect on the environment, although some exceptions exist. Most of the sustainable diet recommendations appear highly cost-effective, but those most commonly promoted on health grounds (e.g., targeting consumption of salt, fruits and vegetables and saturated fat) rank highest in terms of overall efficiency. Moreover, the valuation of benefits indicates that in most cases health benefits are significantly larger than environmental benefits. Overall, the analysis reveals some under-investment in the promotion of sustainable diet recommendations in France. The general lack of enthusiasm in policy circles for informational measures promoting behavioural change may reflect unrealistic expectations about the speed and magnitude of dietary change rather than an objective assessment of the efficiency of those measures

Approche comparative des communautés piscicoles lacustres

The objective of this thesis was to investigate fish community patterns in the lakes of Franceand northeast USA in order to infer the underlying processes. This was achieved using amacroecological approach. Fish communities displayed patterns of addition and replacementof species along environmental gradients related to the lakes' local features and geographiclocation. The structuring role of biotic interactions was not demonstrated. Human-mediatedspecies introductions clearly perturb the relation of local vs. regional species richnesses. Landuse in the lakes' catchments appears to modify guild community structure. The response ofcommunity structure along gradients of temperature and lake size displayed convergencebetween the lakes of France and northeast USA, thereby indicating that that the availabilityof spawning substrates exerts a strong constraint on local communities. These results allowinferring the potential effect of global warming on lake fish communities. Complementarystudies of assembly rules and metacommunity processes should be fruitful for both basic andapplied ecology.L'objectif de cette thèse est de préciser les patrons de variabilité des communautés piscicolesentre les plans d'eau en vue de contribuer à la compréhension des mécanismes qui en sontresponsables, qu'ils soient naturels ou conséquences des activités de l'Homme. Cetteapproche macroécologique des peuplements en France et dans le nord-est des Etats-Unis amontré des patrons d'addition et de remplacement d'espèces en fonction des caractéristiquesabiotiques locales et de la position géographique des plans d'eau. Le rôle structurant desinteractions biotiques est moins évident. Les introductions d'espèces modifient radicalementla relation entre richesses locales et régionales alors que l'occupation agricole et urbaine desbassins versants entraîne des modifications de la structure en guildes des communautés. Laconvergence observée dans la réponse des communautés aux conditions climatiques et à lataille du plan d'eau montre que la disponibilité des habitats de reproduction exerce unecontrainte forte sur les communautés locales et autorise quelques inférences sur lesconséquences du changement climatique global. L'étude des règles d'assemblage et uneréflexion relative au fonctionnement de métacommunautés à l'échelle des bassins versantsoffrent des perspectives sur les plans scientifique et appliqués

Growth and diet of the pikeperch Sander lucioperca (L.) in two French reservoirs. Archives of Polish Fisheries 11(1): 99–114

Abstract. The pikeperch Sander lucioperca (L.) is present in numerous French water bodies. However, few studies have focused on the biology and ecology of the species and, as a result, references are lacking to assess its adaptation to lacustrine environments. The growth and diet of pikeperch were investigated in two reservoirs located in southern France. The fish at both sites show similar growth rates to those reported in other European countries, but slower than those observed in the Camargue. It is faster in the warm, eutrophic waters of the Treignac Reservoir than in the deeper, oligotrophic waters of Castillon Reservoir. A late shift to piscivory with strong cannibalism was observed at both sites, and the condition factors were low. These elements suggest successful adaptation to these environments though shortages of prey fish are likely to occur

Un jeu de données réelles sur les mobilités, quelques applications et de nombreux projets

National audienceCet exposé vise a présenter une base de données réelles sur les mobilités dans une petite agglomération.Depuis plus de deux ans, 17 capteurs disposés dans Châteaubourg mesurent toutes les heures le trafic de voitures, poids-lourds, vélos et piétons en renseignant le sens de transit et la vitesse moyenne des véhicules. Avec environ 750000 données (synchrones et sur des temps longs) pour 7000 habitants, cette agglomération est donc un modèle jouet idéal pour les mobilités, tant sur le plan théorique que pratique.Je montrerais comment ces informations permettent d’analyser le comportement des usagers, de définir des catégories de routes, de quantifier les bouchons ou de comprendre les évolutions sur de longues périodes.Ces données sont en accès libre et un logiciel libre, issue d’une collaboration entre l’association locale Agis-Ta-Terre et des chercheurs de Rennes, permet d’avoir accès à toutes ces informations, que ce soit pour un usage personnel ou de recherche

Analyse microéconométrique d'une politique de transfert des quotas laitiers : le cas des producteurs français

International audienceLes auteurs utilisent les résultats de la théorie de la dualité et le concept de prix virtuel ou dual associé à un "netput" rationné pour analyser le comportement du producteur dans un régime où les quotas peuvent être librement échangés sur un marché. Ils proposent un cadre micro-économique d'analyse du comportement du producteur en régime de quotas échangeables et définissent alors les caractéristiques du marché des quotas à l'équilibre : prix du quota, quantités échangées et variations des revenus des producteurs. Le modèle est appliqué à un échantillon d'exploitations laitières françaises pour l'année 1991