Objective: The 3-day weighed intake is a common assessment tool in nutrition research. There is limited data on the variability of energy and nutrient intake with respect to either the effect of day(s) of recording or the season affect. Both of these issues have practical implications for researchers conducting nutritional assessment studies. Design: Cross-sectional study of dietary intake collected with 7day food diaries. Setting: Aberdeen, North East Scotland, UK between 2002 and 2004. Subjects: Participants recording 7-day intakes from two-long term trials were pooled. In total, there were 260 Caucasian adults with a body mass index range of 16.7 to 49.3 kg/m2 and an age range of 21 to 64 years. Results: Sunday-Tuesday and Wednesday-Friday were not significantly different from the 7day mean (p=0.091 and p=0.451 respectively). Conclusions: