Impact of COVID-19 pandemic on diet behaviour among UK adults: a longitudinal analysis of the HEBECO study
Authors: Dicken Samuel J. , Mitchell John Joseph , Le Vay Jessica Newberry , Beard Emma , Kale Dimitra , Herbec Aleksandra , Shahab Lion 
Published: October 2021

COVID-19 pandemic restrictions impacted dietary habits during the initial months of the pandemic, but long-term effects are unclear. In this longitudinal study, self-selected UK adults (n=1,733) completed three online surveys (May-June, August-September and November-December 2020, with a retrospective pre-pandemic component in the baseline survey), self-reporting sociodemographics, lifestyle and behaviours, including high fat, salt and sugar (HFSS) snacks, HFSS meals and fruit and vegetable (FV) intake. Data were analysed using generalised estimating equations. Monthly HFSS snacks portion intake increased from pre-pandemic levels (48.3) in May-June (57.6, p<0.001), decreased in August-September (43.7, p<0.001), before increasing back to pre-pandemic levels in November-December (49.2, p<0.001). 48.5% self-reported increased (25.9 [95% confidence interval: 24.1, 27.8]) and 47.7% self-reported decreased (24.1 [22.4,26.0]) monthly HFSS snacks portion intakes in November-December compared with pre-pandemic levels. Monthly HFSS meals portion intake decreased from pre-pandemic levels (7.1) in May-June (5.9, p<0.001), being maintained in August-September (5.9, p=0.897), and then increasing again in November-December (6.6, p<0.001), to intakes that remained lower than pre-pandemic levels (p=0.007). 35.2% self-reported increased (4.8 [4.3, 5.3]) and 44.5% self-reported decreased (5.1 [4.6,5.6]) monthly HFSS meals portion intakes in November-December compared with pre-pandemic levels. The proportion meeting FV intake recommendations was stable from pre-pandemic through to August-September (70%), but decreased in November-December 2020 (67%, p=0.034). Increased monthly HFSS snacks intake was associated with female gender, lower quality of life, and - in a time-varying manner - older age and higher HFSS meals intake. Increased monthly HFSS meals intake was associated with female gender, living with adults only and higher HFSS snacks intake. Reduced FV intake was associated with higher body mass index (BMI) and lower physical activity. These results suggest large interindividual variability in dietary change during the first year of the pandemic, with important public health implications in individuals experiencing persistent increases in unhealthy diet choices, associated with BMI, gender, quality of life, living conditions, physical activity and other dietary behaviours.

What is currently known from previous studies

The introduction of lockdown restrictions impacted on diet behaviours during the initial months of the pandemic.

Changes in dietary behaviours have been wide ranging, with individuals making healthy and unhealthy dietary changes in high fat, salt and sugar (HFSS) snacks, HFSS meals and fruit and vegetable (FV) intake.

These dietary changes are associated with multiple sociodemographic, lifestyle and behavioural factors.

Whether dietary changes persist across longer periods of the pandemic, and which factors are associated with any long-term dietary behaviour change is yet to be identified.

What this paper adds

Average UK adult intakes of HFSS snacks and meals fluctuated across the pandemic, with the former returning to pre-pandemic levels and the latter remaining below pre-pandemic levels.

FV intake was stable until the end of 2020, when the proportion meeting recommended intakes declined.

Across the first year of the pandemic, being female and having a lower quality of life were associated with an increase in HFSS snacks intake, whereas the association of age and HFSS meals intake with HFSS snacks intake varied across the pandemic. Living with adults only and having a higher intake of HFSS snacks were associated with an increase in HFSS meals intake. A higher BMI and lower physical activity level were associated with reduced FV intake.