Usual meal times in relation to age, sex, work activity and morningness-eveningness.

Meal-timing is considered an important socio-environmental synchronizer of circadian rhythms and influences human metabolism; the temporal distribution of food intake has also an influence on human performance. In these last years, in industrialized countries, remarkable changes, both in quality and quantity and in timing, have been determined in eating behavior brought about by changes in social and working organization. In this study the authors have verified the usual mealtimes during working and free-days in a population of 670 city-dwellers, 404 men and 266 women, aged between 17 and 60, including students, housewives, clerks, artisans, tradesmen and industrial workers. The results can be summarized as follows: a. the times of the two main meals show a high stability, both in working and in free-days, at about 1230 for lunch and 1915 for dinner, with a higher variability for the dinner-time; b. there are no relevant differences between men and women; c. there is a progressive advance of the breakfast-time (together with sleeping and waking times) with oncoming age; d. industrial workers advance the breakfast-time, on work days, compared to housewives, clerks, artisans and tradesmen, while the latter delay dinner-time as compared to the others; e. shiftwork breaks up the usual timetables interfering with at least one of the main meals, according to the different shifts (morning, afternoon, night); f. morning types anticipate meal and sleeping times in comparison to evening types, both while working and, above all, on free-days.