Geometric and textural properties of food, like unit size, have previously been shown to influence energy intake. While mechanism(s) driving this effect are unclear, unit size may relate to intake by affecting eating microstructure (e.g., eating rate, bite size). In a randomized crossover study, we investigated relationships between unit size, eating microstructure, and intake. Adults (n = 75, 75% women) consumed an snack three times in our laboratory. This snack was a 70-g portion (∼2.5 servings) of one of three sizes of pretzel (small, medium, large). Intake was measured in grams by difference in weight before and after the snack. Each session was video recorded to measure eating microstructure; snack duration (min) and number of bites were annotated and used to calculate mean eating rate (g/min) and mean bite size (g/bite). Results revealed unit size influenced intake (grams and kcal; both p's ≤ 0.001), such that participants consumed 31% and 22% more of the large pretzels (16.9 ± 2.3 g) compared to the small (12.9 ± 2.3 g) and medium sizes (13.8 ± 2.3 g), respectively. Unit size also influenced eating rate and bite size (both p's < 0.001); the largest pretzel size yielded the fastest eating rate and largest mean bite size. Further analysis revealed that after accounting for eating microstructure, the effects of unit size on intake were no longer significant, suggesting eating microstructure was driving these effects. Together, these findings indicate that unit size influences intake by affecting eating microstructure and that food properties like unit size can be leveraged to moderate snack intake.

中文翻译：

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单位大小通过进食率影响零食环境中的随意摄入量

食物的几何和质地特性（例如单位大小）先前已被证明会影响能量摄入。虽然驱动这种效应的机制尚不清楚，但单位大小可能通过影响进食微观结构（例如进食速度、一口大小）而与摄入量相关。在一项随机交叉研究中，我们研究了单位大小、饮食微观结构和摄入量之间的关系。在我们的实验室中，成年人（n = 75，其中 75% 为女性）吃零食 3 次。这种零食是一份 70 克（约 2.5 份）的椒盐卷饼，由三种尺寸（小、中、大）之一组成。通过零食前后的重量差异来测量摄入量，以克为单位。每次会议都进行视频录制，以测量饮食微观结构；注释零食持续时间（分钟）和咬口次数，并用于计算平均进食速度（克/分钟）和平均一口大小（克/口）。结果显示单位大小影响摄入量（克和千卡；p 均≤ 0.001），因此参与者消耗的大椒盐卷饼（16.9 ± 2.3 g）比小椒盐卷饼（12.9 ± 2.3 g）和中等大小椒盐卷饼多消耗 31% 和 22%分别为（13.8 ± 2.3 克）。单位大小也影响进食率和一口大小（p < 0.001）；最大的椒盐卷饼尺寸产生最快的进食速度和最大的平均一口大小。进一步的分析表明，在考虑饮食微观结构后，单位大小对摄入量的影响不再显着，这表明饮食微观结构正在推动这些影响。总之，这些发现表明，单位大小通过影响饮食微观结构来影响摄入量，并且可以利用单位大小等食物特性来调节零食摄入量。