Your Gut Can Sense Sugar, Too
Sugar sensors beyond the tongue detect extra sugar and tell the brain you are full and the body to make more insulin.
TED-Ed · How sugar affects the brain - Nicole AvenaYour gut can sense sugar, even though it cannot taste it.
When you swallow something sweet, the sugar passes through the stomach to the intestines. There it meets a second set of sugar receptors. They are not taste buds like the sweet-taste receptors on your tongue, but they detect sugar and send signals toward the brain.
Sweetness is picked up in two places, first for taste on the tongue and then again in the gut. When you eat extra sugar, those gut sensors signal that you are full and prompt more insulin to handle the added sugar.
Questions people ask
Are the gut sensors actually tasting sweetness?
No. The tongue uses taste buds to create the conscious sensation of sweetness. The gut uses specialized lining cells with some of the same sweet-detecting proteins, but they do not create flavor. They release gut hormones that send chemical and nerve signals to the brain and pancreas.
What does the extra insulin do?
Insulin is a hormone made by the pancreas. After sugar is digested and glucose enters the blood, insulin helps move that glucose from the blood into muscle, fat, and liver cells for energy or storage. That keeps blood sugar from staying too high.
If my gut says I am full, why can I still overeat dessert?
Sweet taste activates the brain's reward system, and with a lot of sugar the dopamine response does not level off the way it does for a familiar balanced meal. That continuing reward may compete with the feeling of fullness from the gut.