JMIR Publications

ABSTRACT

Background:

Online grocery delivery services (OGDS) are a popular way of acquiring food. However, the impact of these services on inequalities in food purchases and diet is under-studied.

Objective:

This study aimed to examine whether the use of OGDS varies by sociodemographic characteristics and is associated with the amount and types of groceries purchased.

Methods:

Item-level take-home food and drink purchase data (n=3,233,920) from households in London and the North of England were available from the 2019 UK Kantar Fast Moving Consumer Goods Panel (n=1911). Purchases were categorised as being bought online or in-store. We used logistic regression to estimate the likelihood of above median frequency of OGDS use by sociodemographic characteristics. We used Poisson regression to estimate: (i) differences in overall energy and nutrients purchased by households that had above and below median OGDS use; and (ii) the proportion of energy purchased from 35 food groups online vs in-store among households that used both shopping methods (n=665).

Results:

Overall, 668 (35.0%) households used OGDS at least once in 2019. Of households that used OGDS, median use was five occasions in 2019. Households were more likely to have above median use in London vs North of England (OR 1.29, 95% CI 1.01 to 1.65) and if they had a higher annual household income (OR 1.56, 95% CI 1.02 to 2.38 for ≥£50,000 vs <£20,000). Households with above median OGDS use purchased a mean of 1,461 kcal (95% CI 1,448 to 1,474) more energy per person per week compared with below median use households. For households that used a combination of in-store and online shopping, online purchases had a larger proportion of energy from vegetables (1.0%, 95% CI 0.2 to 1.8), healthy non-milk-based drinks (1.6%, 95% CI 0.7 to 2.4) and alcohol (1.2%, 95% CI 0.4 to 2.1), and a smaller proportion of energy from less healthy food groups, including puddings and biscuits (-3.3%, 95% CI -4.1 to -2.5) and chocolate and confectionery (-1.5%, 95% CI -2.2 to -0.7) compared to in-store purchases.

Conclusions:

Grocery purchases made online appeared healthier, but households with above median OGDS use purchased more energy from groceries overall. The extra energy purchased among households with above median OGDS use, compared with below median OGDS use, could lead to over-consumption or food waste. Alternatively, more energy purchased for in-home consumption could be because these households eat out less. If this is the case, total diet quality may be better for OGDS users in terms of healthiness of grocery purchases and frequency of out-of-home food purchasing. Future research should explore potential public health implications.