The aim of the present study was to describe the energy, nutrient and crude v. disaggregated food intake measured using 7 d diet diaries (7dDD) for the full baseline Norfolk cohort recruited for the European Prospective Investigation into Cancer (EPIC-Norfolk) study, with emphasis on methodological issues. The first data collection took place between 1993 and 1998 in Norfolk, East Anglia (UK). Of the 30 445 men and women, aged 40–79 years, registered with a general practitioner invited to participate in the study, 25 639 came for a health examination and were asked to complete a 7dDD. Data from diaries with data recorded for at least 1 d were obtained for 99 % members of the cohort; 10 354 (89·8 %) of the men and 12 779 (91·5 %) of the women completed the diet diaries for all 7 d. Mean energy intake (EI) was 9·44 (sd 2·22) MJ/d and 7·15 (sd 1·66) MJ/d, respectively. EI remained approximately stable across the days, but there was apparent under-reporting among the participants, especially among those with BMI >25 kg/m2. Micronutrient density was higher among women than among men. In conclusion, under-reporting is an issue, but not more so than that found in national surveys. How foods were grouped (crude or disaggregated) made a difference to the estimates obtained, and comparison of intakes showed wide limits of agreement. The choice of variables influences estimates obtained from the food group data; while this may not alter the ranking of individuals within studies, this issue may be relevant when comparing absolute food intakes between studies.

Little is known about changes in dietary patterns over time. The present study aims to derive dietary patterns using cluster analysis at three ages in children and track these patterns over time. In all, 3 d diet diaries were completed for children from the Avon Longitudinal Study of Parents and Children at 7, 10 and 13 years. Children were grouped based on the similarities between average weight consumed (g/d) of sixty-two food groups using k-means cluster analysis. A total of four clusters were obtained at each age, with very similar patterns being described at each time point: Processed (high consumption of processed foods, chips and soft drinks), Healthy (high consumption of high-fibre bread, fruit, vegetables and water), Traditional (high consumption of meat, potatoes and vegetables) and Packed Lunch (high consumption of white bread, sandwich fillings and snacks). The number of children remaining in the same cluster at different ages was reasonably high: 50 and 43 % of children in the Healthy and Processed clusters, respectively, at age 7 years were in the same clusters at age 13 years. Maternal education was the strongest predictor of remaining in the Healthy cluster at each time point – children whose mothers had the highest level of education were nine times more likely to remain in that cluster compared to those with the lowest. Cluster analysis provides a simple way of examining changes in dietary patterns over time, and similar underlying patterns of diet at two ages during late childhood, that persisted through to early adolescence.