Is eating home-prepared food a necessary condition for high dietary quality? Cross-sectional analysis of the UK National Diet and Nutrition Survey, 2008–16

Background Despite inconclusive evidence, the idea that home food preparation and skills are a limiting factor in achieving a healthy diet is widespread, and corresponding skills interventions and dietary guidelines proliferate. The aim of this study was to determine whether eating home-prepared (HP) food is a necessary condition for high dietary quality by exploring whether individuals can eat healthily while consuming little HP food. Methods A cross-sectional analysis of a subsample of the UK National Diet and Nutrition Survey (2008–16) was conducted. Adult participants were included if they were in the top tertile of diet quality (determined with a Dietary Approaches to Stopping Hypertension [DASH] index derived from 4-day food diaries), and in the bottom or top tertile of proportion of energy from HP food. Regression models were used to determine whether belonging to the low HP group was associated with sociodemographic characteristics, DASH score, energy intake, prevalence of obesity, and dietary composition, relative to the high HP reference group. Findings Of the total adult survey sample (n=6364), 1063 were in the top tertile of diet quality (442 [7·0%] low HP, high diet quality group, 621 [9·8%] high HP, high diet quality group). Participants in the low HP group were more likely to be older and white, and less likely to have a degree-level education, than those in the high HP group. After adjustment for these factors, there were no differences in DASH score, energy intake, or obesity prevalence between the groups. Participants in the low HP group consumed more fruit (additional 30·81 g per day, 95% CI 5·51–56·11) and less red meat (−10·43, −4·31 to −16·56) than did participants in the high HP group, but also more sugar (11·58, 7·54–15·61) and sodium (107·78, 13·79–201·76). Interpretation We found that eating HP food is not a prerequisite for high dietary quality. Interventions should learn from individuals who eat well with minimal contribution from HP food, and support all types of eaters to eat healthily. Funding Centre for Diet and Activity Research, a UKCRC Public Health Research Centre of Excellence (for CCA, JA, and TP).