Comparing supermarket loyalty card data with traditional diet survey data for understanding how protein is purchased and consumed in older adults for the UK, 2014-16

Mark A. Green* (Corresponding Author), Anthony W Watson, Jeffrey M Brunstrom, Bernard M Corfe, Alex Johnstone, Elizabeth A Williams, Emma J Stevenson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)
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Our ability to understand population-level dietary intake patterns is dependent on having access to high quality data. Diet surveys are common diet assessment methods, but can be limited by bias associated with under-reporting. Food purchases tracked using supermarket loyalty card records may supplement traditional surveys, however they are rarely available to academics and policy makers. The aim of our study is to explore population level patterns of protein purchasing and consumption in ageing adults (40 years onwards).

We used diet survey data from the National Diet and Nutrition Survey (2014–16) on food consumption, and loyalty card records on food purchases from a major high street supermarket retailer (2016–17) covering the UK. We computed the percentage of total energy derived from protein, protein intake per kg of body mass, and percentage of protein acquired by food type.

We found that protein consumption (as the percentage of total energy purchased) increased between ages 40–65 years, and declined thereafter. In comparison, protein purchased in supermarkets was roughly 2–2.5 percentage points lower at each year of age. The proportion of adults meeting recommended levels of protein was lowest in age groups 55–69 and 70+. The time of protein consumption was skewed towards evening meals, with low intakes during breakfast or between main meals. Meat, fish and poultry dominated as sources of protein purchased and consumed, although adults also acquired a large share of their protein from dairy and bread, with little from plant protein.

Our study provides novel insights into how protein is purchased and consumed by ageing adults in the UK. Supermarket loyalty card data can reveal patterns of protein purchasing that when combined with traditional sources of dietary intake may enhance our understanding of dietary behaviours.
Original languageEnglish
Article number83
Number of pages10
JournalNutrition Journal
Publication statusPublished - 13 Aug 2020

Bibliographical note

The project was funded by the Research Councils UK ‘Priming Food Partnerships’ initiative supported by BBSRC, MRC, EPSRC and ESRC. Project reference number – BB/P023886/1. Thank you to the High Street Retailer for supplying the data.


  • protein
  • big data
  • supermarket loyalty cards
  • diet surveys
  • population
  • Supermarket loyalty cards
  • Population
  • Big data
  • Diet surveys
  • Protein


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