Salad and satiety. The effect of timing of salad consumption on meal energy intake

Abstract

In a previous study, consuming a fixed amount of low-energy-dense salad as a first course reduced meal energy intake. We investigated whether this effect depended on serving salad before rather than with the main course, or on compulsory rather than ad libitum consumption. On five occasions, 46 women consumed ad libitum a main course of pasta, accompanied four times by low-energy-dense salad (300 g; 100 kcal [418 kJ]). At two meals the salad was served 20 min before the pasta (once compulsory; once ad libitum), and at two meals the salad was served with the pasta (once compulsory; once ad libitum). Results showed that adding a fixed amount of salad to the meal reduced energy intake by 11% (57±19 kcal [238±79 kJ]). Ad libitum salad consumption was less than compulsory consumption and did not significantly affect energy intake. Across all participants, the timing of serving the salad did not significantly influence energy intake, but the effect of timing depended on participant scores for flexible dietary restraint. Consuming low-energy-dense salad before rather than with the main course increased vegetable consumption by 23%. To moderate energy intake, maximizing the amount of salad eaten may be more important than the timing of consumption.

Figure 1

Energy intake (mean ± SEM) of 46 women at meals in which the consumption of salad was either ad libitum or fixed, and the timing of consumption was either before or with the main course of pasta. At one meal, no salad was served. Among the four salad conditions, different letters for the same meal component indicate significant differences according to a mixed linear model with repeated measures (p < 0.036). For the no-salad condition, letters indicate significant differences from the four salad conditions according to a separate mixed model with a Dunnett-Hsu adjustment for multiple comparisons (p < 0.012).

Figure 2

Meal energy intakes of 46 women who consumed a salad either before or with the main course of pasta, in relation to participant scores for flexible control of restraint. The slopes of the regression lines were significantly different according to an analysis of covariance using a mixed linear model with repeated measures (p = 0.018). Women with the lowest score (0) consumed 56 ± 27 kcal [234 ± 113 kJ] less energy when the salad was served before the main course and women with the highest score (6) consumed 67 ± 30 kcal [280 ± 126 kJ] less energy when the salad was served along with the main course. Energy intakes are combined for the conditions of fixed and ad libitum intake, which did not influence this outcome.