A study published in Flavour shows that thicker drinks are more likely to make you feel full and keep feeling that way longer for the same amount of calories than thin drinks. Creaminess also boosted people’s ratings of how full a drink would make them, but didn’t have an impact on expectations about satiety in comparison to solid food. Figuring out how to make drinks feel more filling without increasing their caloric content could help minimize that disconnect and possibly mitigate the impact on weight, the researchers theorized.
The researchers first tested how sensitive untrained people were to thickness by presenting them with a fruit yogurt drink to which varying amounts of tara gum had been added to alter its viscosity. Across the 16 different gradations, people perceived greater thickness, creaminess, and stickiness with rising amounts of the thickener.
Next, the experiments expanded to test the effect of combinations of thin, thick, creamy, and high or low calories on satiety. The 25 university staff and students participating (none were obese) sampled eight different versions of the yogurt drink and rated them by how big a serving of pasta with tomato sauce they thought it could replace for lunch, to have the same impact on hunger. Thickness and creamy flavor both had an impact on how filling the drink was expected to be, without significant interaction between the two factors. The actual energy content of the drinks didn’t correlate with ratings of how filling the drink was expected to be, nor were there interactions with thickness or creaminess.
When it came to satiety measured in pasta-equivalents, the thicker drinks got higher ratings than the thin versions. Creamy flavor didn’t boost the expected impact on hunger, nor did calorie content make a difference in analyses adjusted for multiple comparisons.
These results suggest that “creamy” alone isn’t enough for the general consumer, the researchers pointed out. They cautioned, though, that the creamy drinks were rated as thicker as well, “so we cannot rule out the possibility that the creamy drinks were instead expected to be more filling, based on their enhanced perceived thickness.”
Another possible explanation for the unexpected disconnect between satiety and filling is that texture was a more relevant cue for satiety when asked to imagine it in comparison to a plate of pasta, whereas creaminess went overlooked as a factor not generally associated with pasta and tomato sauce.