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Marion Tharrey - FoodScapes flagship Project: "Impact of community gardening participation on the adoption of more sustainable lifestyles"

Marion Tharrey will defend her thesis entitled "Impact of community gardening participation on the adoption of more sustainable lifestyles" on 14 December at 2pm. Her thesis will be broadcast live on the SupAgro YouTube channel (https://www.youtube.com/channel/UCsZAs3L5-yp53sYf4sZnnFg ).

Carried out as part of the FoodScpaes flagship project, and financed by Agropolis Fondation, her thesis work was supervised by Nicole Darmon and Pascale Scheromm. Marion was hosted for three years at the UMR MOISA (INRAE). She is the first PhD student of the FoodScapes project to defend her thesis.


With more than 70% of the European population living in urban settlements, and an expected increase in this number in the foreseeable future, cities are important determinants of future sustainability and human health. However, urban environment can promote unhealthy lifestyles (such as unhealthy diets, sedentary behavior, sleep deprivation, abusive use of alcohol and cigarettes) that are known to increase the risk of chronic non-communicable diseases, a major public health challenge today. In addition, urbanization also has serious consequences for the environment.
Cities, responsible for nearly 70% of global greenhouse gas emissions, contribute significantly to global warming. It is therefore essential to find strategies to improve people’s health while promoting sustainable urban management. This implies in particular reconsidering the place of plants and biodiversity in new urban planning projects in order to reconnect the health of people and ecosystems. In particular, exposure to nature and green spaces are known to have a beneficial effect on health and well-being buy there impact on physical activity, social contacts, stress and air quality.
Hence the presence of green spaces in urban settings are gaining recognition as a way to link ecosystems and human health and may help achieve more sustainable cities and communities. Among the different types of green space, community gardens (defined as a plot of land gardened collectively by a group of people living in an urban area) are providing an additional advantage of offering a place to grow fresh fruit and vegetables, which may help more sustainable food systems to develop.
A growing body of literature suggests that community gardens have many benefits on health and well-being by fostering fruit and vegetable consumption, physical activity, as well as mental and social well-being. Nevertheless, the studies conducted to date have mainly been conducted in North American contexts and the results have yet to be confirmed in a French context that differs in its social, political and urban history.
In addition, studies using a longitudinal design with a sufficient sample size are needed to validate emerging hypotheses from qualitative interviews and from cross sectional studies, which still dominate the scientific literature in this field of research. Longitudinal studies with control groups are the only ones that can explore the causal impact of a natural intervention or experiment (e.g., a change in the environment of individuals, not induced by research) on individuals’ behaviors, including their health behaviors.
However, these type of studies do not exist concerning participation in a community garden, considered here as a natural experiment. While several studies indicate healthier behaviors among participants in a community garden than among non-gardeners, it is still unclear whether these positive behaviors are related to garden attendance or pre-existed before entering the garden (and may even explain the choice to join a community garden).
The major assumption of this thesis is that participation in a community garden can induce changes in people’s perceptions and behaviors, leading them to adopt more sustainable lifestyles. We define more sustainable lifestyles by more favorable attitudes or behaviors on three dimensions of sustainability, namely social/health, environmental and economic.
To test this hypothesis we developed a quasi-experimental study protocol with a group exposed to a natural experimentation (gardeners entering a community garden) and a control group, and some components of their lifestyles were observed when they enter the garden and one year later. Participants were given three tools to characterize their lifestyles: a food supply diary recording household food supply over one-month periode, an accelerometer (Actigraph) measuring participant’s physical activity for 9 days, and an online questionnaire on mental and social health, sensitivity to food waste and connection to nature. Lifestyle sustainability was measured by

1) the nutritional quality of food supply, physical activity, mental well-being and social connection (social/health dimension),

2) the environmental impact of household’s food supply and related food trips, concern for food waste and connection to nature (environmental dimension),

3) household food expenditure and the share of garden produce in gardeners’ food supplies (economic dimension).

If lifestyles are improved only in the experimental group, this design will establish a causal relationship between participation in a community garden and the adoption of more sustainable lifestyles. The objective of this thesis is therefore to explore the impact of participation in a community garden on the adoption of more sustainable lifestyles in a French context. At a time when many cities are considering the integration of community gardens on their territories, this thesis will provide valuable data on the role of community gardens as a tool for promoting more sustainable lifestyles.