Whenever I feel a little light headed or tired, it helps to eat something sweet. Specifically, simply chewing or sucking on a sweet seems to aleviate the symptoms within a matter of seconds and then the sugar seems to kick in. So I was wondering whether it is just a psychological effect, or whether sugars are absorbed in our mouth and reach the brain (or wherever the sugars exert their effects?) within seconds. Or is perhaps the taste of sugar sufficient to signal the body that it can safely release some extra energy as resupply is imminent?

  • $\begingroup$ Welcome to Biology.SE! You can make the experience yourself. Put a piece of bread in your mouth for several minutes. Don't chew (would be cheating) and see how the bread starts to degrade. $\endgroup$
    – Remi.b
    May 25, 2015 at 22:22
  • $\begingroup$ @RoryM - is this a duplicate? I think OP is basically asking whether the sugar can kick in within seconds. Although this is addressed in the linked question, it is not answered there as such. I vote to re-open after edits in this question. $\endgroup$
    – AliceD
    May 26, 2015 at 3:16
  • $\begingroup$ @user3461075 - could you verify that it is a few seconds? $\endgroup$
    – AliceD
    May 26, 2015 at 3:21
  • 1
    $\begingroup$ @AliceD Thank you. You did point out the essential question of this matter. The effect really occurs within seconds. $\endgroup$ May 26, 2015 at 14:55
  • $\begingroup$ @AliceD Speed is answered in the first answer as far as I can tell? $\endgroup$
    – Rory M
    May 27, 2015 at 17:48

1 Answer 1


Yes we do. The first part of digestion starts in mouth. Digestion begins in the mouth, where chemical and mechanical digestion occurs. Saliva produced by the salivary glands (located under the tongue and near the lower jaw), is released into the mouth. Saliva begins to break down the food, moistening it and making it easier to swallow. A digestive enzyme (amylase) in the saliva begins to break down the carbohydrates (starches and sugars). 


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