Researchers from Wageningen University in the Netherlands and the Nestlé Research Center in Switzerland sought to investigate the contribution to satiety of both oral and gastric stimulation, measured as subjective appetite rating, as well as energy intake.
On five non-consecutive days, they instructed 26 healthy men to chew but not swallow food for one or eight minutes, while their stomachs were infused with different amounts of the same food via a nasogastric tube. In the control condition, participants were fitted with a nasogastric tube but were given no food, either to chew or directly into the stomach.
Thirty minutes later, the participants were given a meal and invited to eat as much as they liked until comfortably full.
“Duration of oral exposure was at least as important in decreasing energy intake as gastric filling volume,” they found.
All conditions with gastric and oral stimulation decreased appetite compared to the control condition, but longer chewing times were associated with a 19% lower energy intake at the subsequent meal with a 100ml solution, and 15% lower with an 800ml solution containing the same number of calories. On the other hand, the 800ml gastric volume did not suppress subsequent energy intake more than the 100ml conditions.
“Our findings suggest longer oral-sensory stimulation may be an important factor in lowering energy intake,” said Dr Alfrun Erkner, a Nestlé Research Center scientist involved in the study.
She added: “This doesn’t necessarily mean specially-designed nutrition beverages can’t have a satiating effect, but that products that provide increased oral stimulation could be more effective.
“Follow-up studies are needed for a better understanding of the impact of the interaction of oral and gastric factors on eating behaviour.”
The researchers concluded that foods intended to increase satiety may work best if they involve high levels of oral sensory stimulation.
“Effects of Oral and Gastric Stimulation on Appetite and Energy Intake”
Authors: Anne G.M. Wijlens, Alfrun Erkner, Erin Alexander, Monica Mars, Paul A.M. Smeets and Cees de Graaf