Do smaller bites or more time in the mouth reduce how much people eat?

Details

The experiment was part of a thesis investigating how food texture affects how much people eat before stopping. With a semi-solid test food, participants ate an average of 42 g less when time spent processing each mouthful was fixed at 9 seconds rather than 3 seconds. They ate an average of 106 g less with bites fixed at about 5 g rather than about 15 g. These were separate comparisons, not a combined reduction.

Other experiments help put this finding in context. A study of food thickness included 108 participants and found lower intake of a thicker, semi-solid product than a liquid product, with intake differences ranging from 29% to 34% across settings. A separate study of eating effort and speed included 49 participants: the liquid was consumed faster, and setting a standard eating rate led to similar intakes. In a study with 33 participants, fixed amounts of the liquid and semi-solid products produced similar responses in the digestive hormones measured, so those responses did not explain the intake difference.

The results were not uniform across foods. Changing the texture of solid foods in a separate study with 106 participants did not change intake. The authors suggested that the texture differences may have been too subtle to alter eating speed. A separate observational study of 54 normal-weight and overweight participants found small to no differences between the groups in eating behavior or the release of food aromas toward the nose during eating. Overall, the findings support a role for how food is handled in the mouth under the tested conditions; the abstract does not establish long-term effects on body weight.