The sweet taste of sugar captivates palates worldwide. In Austria and Germany, annual per-person consumption averages 33 and 34 kilograms, respectively. As sugar's role in diets and health—particularly body weight—grows, understanding its molecular mechanisms on appetite, beyond mere calories, remains crucial.
Sweet Taste Receptors and Satiety Regulation "We examined how activating sweet taste receptors influences satiety," explains Veronika Somoza, Deputy Head of the Department of Physiological Chemistry at the University of Vienna and Director of the Leibniz Institute of Food Systems Biology at the Technical University of Munich.
In a blinded, crossover intervention study, researchers tested glucose and sucrose solutions on 27 healthy men aged 18-45. Participants consumed a 10% (weight/volume) glucose or sucrose solution, or the same with 60 ppm lactisol—a compound that binds to a sweet receptor subunit, dulling sweetness perception. All solutions matched in energy content. Two hours later, subjects ate ad libitum breakfast. Blood samples and body temperature were monitored before and during the 120-minute wait.
Average 100 Extra Kilocalories
After the lactisol-sucrose solution, breakfast energy intake rose 13%—about 100 kilocalories more—than plain sucrose. This group also had lower body temperature and reduced plasma serotonin levels. Serotonin, a neurotransmitter and hormone, helps suppress appetite. No such effects appeared with glucose solutions.
"These results indicate sucrose modulates satiety and energy intake via sweet taste receptors, independent of calories," notes Barbara Lieder from the University of Vienna.
Lead author Kerstin Schweiger adds: "The lack of lactisol effect with glucose may stem from differing receptor activation by glucose versus sucrose. Non-receptor mechanisms likely play a role too."
"Much remains to uncover about sugar, taste receptors, and satiety at the molecular level," Somoza concludes. Sweet receptors in the gut add further complexity, but this research marks vital progress.
