Dip increases eating rate and promotes greater intake even when energy density is reduced

Increasing food lubricity by adding dip increases eating rate; however it remains unclear if such manipulation influences energy intake of a snack, or how this might combine with energy density (ED) to affect risk of energy overconsumption. Here, we used pretzels and hummus to investigate the effects of oral lubrication (with vs. without hummus) and ED on snack intake. Adults (n = 46, 67 % female) were video recorded while consuming a 70 ± 2 g pretzel snack (∼2.5 servings) ad libitum 3 times in our laboratory: once each with reduced-ED hummus, matched-ED hummus, and no hummus (control). Both hummuses were ∼ 110 g (∼4 oz). Intake was measured, and video recordings were used to assess eating rate. Consistent with the expected effects of increasing lubricity, pretzel and total snack eating rates were faster in the hummus conditions vs. the control (all p's < 0.001), indicating that hummus increased lubricity and facilitated faster consumption. More was consumed of the pretzels and total snack in the hummus conditions compared to the control (all p's < 0.001), suggesting that increased lubricity promoted intake. Although ED did not completely mitigate the effects of lubricity on pretzel and total snack energy intake, it did moderate these effects (matched > reduced > control; all p's < 0.001). Overall, including hummus increased eating rate, presumably by increasing snack lubricity, and the commensurate increase in intake persisted even when the dip had a lower ED. Thus, consumption of snacks lower in ED and without lubricating dips may be an effective way to help reduce energy intake.