Individual Differences in Adaptation to Sweet Taste

Over-consumption of sugar-sweetened beverages is associated with obesity and related conditions, but low-calorie alternatives are rejected by most consumers. Individual differences in sensitivity to off tastes of low-calorie sweeteners (LCS) have been considered as a factor in consumer choice. However, potential differences in adaptation, i.e., the tendency for sweetness to wane with repeated sips, has received less attention. This study measured sweetness adaption to a sugar and two LCS in the same sample of healthy adults to determine if there are stable individual differences in sweet adaptation. Stimuli included three sweeteners at concentrations corresponding to the low (500 mM glucose, 246 µM sucralose, and 303 µM RebA) and high (1.08 M glucose, 870 µM sucralose, and 823 µM RebA) end of the sweetness spectrum for most commercially sold beverages in the US. Each trial participants (n = 38) tasted seven, 10 mL samples of the same stimulus (10 s between samples). For each sample, participants rated sweetness intensity using a general Labeled Magnitude Scale. Tests for all stimuli were repeated three times, on separate days, to assess stability. All sweeteners showed significant reduction in sweetness with repeated sips, with the exception of the higher concentration glucose (no significant decrease across repeated sips). Sweetness waned with repeated sips more profoundly for the two LCS than for glucose, as expected given previous results. Importantly, there were substantial and stable (across test sessions) individual differences in sweet adaptation. Sweetness faded more rapidly and completely for LCS than for glucose, and some individuals were more susceptible to sweetness adaptation than others. Whether these individual differences are stable across longer periods of time, or contribute to individual differences in acceptance of beverages sweetened with LCS is currently unclear. Funded by a consortium of food and ingredient companies, including Asahi, Kellogg, Kraft, Mondelez, and Suntory. The views expressed are those of the authors, and do not necessarily reflect the views of the sponsors.