[Frequency of food consumption in children. Weekdays versus weekends].

The accurate assessment of nutritional quality or of food eating frequency in epidemiologic studies depends among other things on the internal validity of the method. The purpose of this study was to compare the mean food eating frequencies at meals and between-meals of 20 specific food items obtained from a two-weekday-diet record to those obtained from one weekend-day. A three-day-diet record including a weekend-day was completed by 549 eleven-year old children with the help of their parents. For each pair of food frequencies observed, a Student t test was performed. The results showed that when comparing the means for two weekdays to one weekend-day, significant differences (p less than 0.05) were observed for soft drinks, pastries, milk and vegetables. Also fruit juices, whole grain cereals, fresh fruits, milk, green and yellow vegetables were eaten significantly less at meals during the weekend-day. Between-meal eating is generally more salted or more sweetened during the weekend-day. Foods generally considered to be more nutritious are eaten less during the weekend-day. The differences in food frequencies obtained showed the need of including one weekend-day in a three-day-diet record to avoid the overestimation of food consumption and of the quality of the diet.