Patterns of week-to-week table-salt use by men and women consuming constant diets

Ad-libitum table-salt use by subjects on constant diets was analysed to determine patterns of individual consistency or variation. Data were obtained from two studies in which free-living subjects ate all meals in a metabolic unit. In one study, 24 men consumed a diet constant in all respects except caloric level and source of dietary fibre over an 80-day period. In the other study, 13 women consumed a diet which varied only in caloric level and riboflavin content over a 67-day period. The menu for each study consisted of a conventional breakfast, lunch, dinner and snacks. Table-salt use was recorded as week-to-week weights of individually assigned salt shakers. Large and significant interindividual differences were observed in the amounts of salt added to the same menu. In contrast, a high degree of intraindividual consistency in salt use was observed from week-to-week and, among the women, across menstrual cycle phases. When food portions were increased during the second half of the men's study, table-salt use increased but the amount used per 1000 kcal remained relatively constant. In both sexes, variance in salt use increased proportionately with the mean.