Cristina Stewart

Ms. Cristina Stewart

University of Oxford
orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2022 in Science of The Total Environment
Verified
Journal Article
Open access
CACarmelia Alae-Carew
Carmelia Alae-Carew
RGRosemary Green
Rosemary Green
CSCristina Stewart
Cristina Stewart
BCBrian Cook
Brian Cook
ADAlan D. Dangour
Alan D. Dangour
PSPauline Scheelbeek
Pauline Scheelbeek
A global transformation towards sustainable food systems is crucial for delivering on climate change mitigation targets worldwide. In high- and middle-income settings, plant-based meat and dairy alternatives present potential substitutes for animal sourced foods, and a pathway to transition to more sustainable diets.

20 February 2021 in Environment and Behavior
Verified
Journal Article
Open access
PDF file
CPChristina Potter
Christina Potter
ABAnastasios Bastounis
Anastasios Bastounis
JHJamie Hartmann-Boyce
Jamie Hartmann-Boyce
CSCristina Stewart
Cristina Stewart
KFKerstin Frie
Kerstin Frie
SJSusan A. Jebb
Susan A. Jebb
This review assessed the effects of environmental labels on consumers’ demand for more sustainable food products. Six electronic databases were searched for experimental studies of ecolabels and food choices. We followed standard Cochrane methods and results were synthesized using vote counting. Fifty-six studies (N = 42,768 participants, 76 interventions) were included. Outcomes comprised selection (n = 14), purchase (n = 40) and consumption (n = 2). The ecolabel was presented as text (n = 36), logo (n = 13) or combination (n = 27). Message types included: organic (n = 25), environmentally sustainable (n = 27), greenhouse gas emissions (n = 17), and assorted “other” message types (n = 7). Ecolabels were tested in actual (n = 15) and hypothetical (n = 41) environments. Thirty-nine studies received an unclear or high RoB rating. Sixty comparisons favored the intervention and 16 favored control. Ecolabeling with a variety of messages and formats was associated with the selection and purchase of more sustainable food products.

7 October 2021 in The Lancet Planetary Health
Verified
Journal Article
Open access
CSCristina Stewart
Cristina Stewart
CPCarmen Piernas
Carmen Piernas
BCBrian Cook
Brian Cook
SJSusan A Jebb
Susan A Jebb
High meat consumption, particularly red meat and processed meat, negatively affects our health, while meat production is one of the largest contributors to global warming and environmental degradation. The aim of our study was to explore trends in meat consumption within the UK and the associated changes in environmental impact. We also aimed to identify any differences in intake associated with gender, ethnicity, socioeconomic status, and year of birth. Our study aimed to describe consumption of red, white, and processed meat within the UK, using data from the National Diet and Nutrition Survey rolling programme (2008–09 to 2018–19), and the associated changes in environmental impact. Meat consumption was based on disaggregated meat data, from 4 day food diaries that excluded all non-meat components of composite dishes. For each year surveyed, trends for meat intake were reported as mean grams per capita per day and linear-regression models were used to test for trends. We used multivariable linear-regression models to examine differences among consumers, as a percentage of food energy, by gender, ethnicity, equivalised household income, and year of birth. From 2008 to 2019, average meat consumption per capita per day decreased from 103·7 g (SE 2·3) to 86·3 g (2·9) per day (ptrend<0·0001), including an absolute reduction in red-meat consumption of 13·7 g (ptrend<0·0001), an absolute reduction in processed meat consumption of 7·0 g (ptrend<0·0001), and a 3·2 g increase (ptrend=0·0027) in white-meat consumption. Collectively, these changes were associated with a significant reduction in all six environmental indicators over the whole period. The two middle birth-year groups (people born in 1960–79 and 1980–99) and White individuals were the highest meat consumers. Meat intake increased over time among people born after 1999, was unchanged among Asian and Asian British populations, and decreased in all other population subgroups. We found no difference in intake with gender or household income. Despite the overall reduction in meat intake, reaching meat-consumption targets that align with sustainable diets will require a substantial acceleration of this trend. The Wellcome Trust, Our Planet Our Health programme (Livestock, Environment, and People).

27 December 2021 in The American Journal of Clinical Nutrition
Verified
Journal Article
Open access
PDF file
FBFilippo Bianchi
Filippo Bianchi
CSCristina Stewart
Cristina Stewart
NANerys M Astbury
Nerys M Astbury
BCBrian Cook
Brian Cook
PAPaul Aveyard
Paul Aveyard
SJSusan A Jebb
Susan A Jebb
Reducing meat consumption could protect the environment and human health. We tested the impact of a behavioral intervention to reduce meat consumption. Adult volunteers who regularly consumed meat were recruited from the general public and randomized 1:1 to an intervention or control condition. The intervention comprised free meat substitutes for 4 weeks, information about the benefits of eating less meat, success stories, and recipes. The control group received no intervention or advice on dietary change. The primary outcome was daily meat consumption after 4 weeks, assessed by a 7-day food diary, and repeated after 8 weeks as a secondary outcome. Other secondary and exploratory outcomes included the consumption of meat substitutes, cardiovascular risk factors, psychosocial variables related to meat consumption, and the nutritional composition of the diet. We also estimated the intervention's environmental impact. We evaluated the intervention using generalized linear mixed-effects models. Between June 2018 and October 2019, 115 participants were randomized. The baseline meat consumption values were 134 g/d in the control group and 130 g/d in the intervention group. Relative to the control condition, the intervention reduced meat consumption at 4 weeks by 63 g/d (95% CI: 44–82; P < 0.0001; n = 114) and at 8 weeks by 39 g/d (95% CI: 16–62; P = 0.0009; n = 113), adjusting for sex and baseline consumption. The intervention significantly increased the consumption of meat substitutes without changing the intakes of other principal food groups. The intervention increased intentions, positive attitudes, perceived control, and subjective norms of eating a low-meat diet and using meat substitutes, and decreased attachment to meat. At 8 weeks, 55% of intervention recipients identified as meat eaters, compared to 89% of participants in the control group. A behavioral program involving free meat substitutes can reduce meat intake and change psychosocial constructs consistent with a sustained reduction in meat intake.

1 February 2022 in Appetite
Verified
Journal Article
Open access
EÇElif Naz Çoker
Elif Naz Çoker
RPRachel Pechey
Rachel Pechey
KFKerstin Frie
Kerstin Frie
SJSusan A. Jebb
Susan A. Jebb
CSCristina Stewart
Cristina Stewart
BCBrian Cook
Brian Cook
Perceptions of social norms around eating behavior can influence food choices. Communicating information about how others are changing their eating behavior over time (dynamic descriptive social norms) may motivate individuals to change their own food selection and consumption. Following a four-week baseline period, 22 in-store restaurants of a major retail chain across the UK were randomized to display a dynamic descriptive social norm message intended to motivate a shift from meat-to plant-based meals either during the first two, or last two weeks of the four-week study period. A linear regression model showed there was no evidence of an effect of the intervention (β = -0.022, p = .978, 95% CIs: −1.63, 1.58) on the percentage sales of meat- vs plant-based dishes. Fidelity checks indicated that adherence to the intervention procedure was often low, with inconsistencies in the placement and display of the intervention message. In four stores with high fidelity the estimated impact of the intervention was not materially different. The lack of apparent effectiveness of the intervention may reflect poor efficacy of the intervention or limitations in its implementation in a complex food purchasing environment. The challenges highlighted by this study should be considered in future design and evaluation of field trials in real-world settings.

15 July 2021 in PLOS Medicine
Verified
Journal Article
Open access
PDF file
CPCarmen Piernas
Carmen Piernas
BCBrian Cook
Brian Cook
RSRichard Stevens
Richard Stevens
CSCristina Stewart
Cristina Stewart
JHJennifer Hollowell
Jennifer Hollowell
SJSusan A. Jebb
Susan A. Jebb
Background: Reducing meat consumption could bring health and environmental benefits, but there is little research to date on effective interventions to achieve this. A non-randomised controlled intervention study was used to evaluate whether prominent positioning of meat-free products in the meat aisle was associated with a change in weekly mean sales of meat and meat-free products. Methods and findings: Weekly sales data were obtained from 108 stores: 20 intervention stores that moved a selection of 26 meat-free products into a newly created meat-free bay within the meat aisle and 88 matched control stores. The primary outcome analysis used a hierarchical negative binomial model to compare changes in weekly sales (units) of meat products sold in intervention versus control stores during the main intervention period (Phase I: February 2019 to April 2019). Interrupted time series analysis was also used to evaluate the effects of the Phase I intervention. Moreover, 8 of the 20 stores enhanced the intervention from August 2019 onwards (Phase II intervention) by adding a second bay of meat-free products into the meat aisle, which was evaluated following the same analytical methods. During the Phase I intervention, sales of meat products (units/store/week) decreased in intervention (approximately −6%) and control stores (−5%) without significant differences (incidence rate ratio [IRR] 1.01 [95% CI 0.95–1.07]. Sales of meat-free products increased significantly more in the intervention (+31%) compared to the control stores (+6%; IRR 1.43 [95% CI 1.30–1.57]), mostly due to increased sales of meat-free burgers, mince, and sausages. Consistent results were observed in interrupted time series analyses where the effect of the Phase II intervention was significant in intervention versus control stores. Conclusions: Prominent positioning of meat-free products into the meat aisle in a supermarket was not effective in reducing sales of meat products, but successfully increased sales of meat-free alternatives in the longer term. A preregistered protocol (https://osf.io/qmz3a/) was completed and fully available before data analysis.