Question

Why does a sip of tea taste less sweet than usual after eating something very sweet?

Answer 1

HELLO FRIEND HERE IS YOUR ANSWER,,,,,,,
This is a good question brother,,,

Normally when something sweet is tasted in something we have eaten before the Brain is adapted and accustomed to that $\textbf{"Sweetness index"}$ and that index is higher than the one in the tea. So the Brain will receive that electrically inducted signal of a "more sweeter substance" and another sweet substance like the tea is more or less compared and equal to it reminds itself of the previous index,, this makes it to pass the signal .

In this case the total Sweetness is never decreased, it maintains its pact,, the tongue cannot detect the Sweetness of the tea as it is less. This particular method or derived method from Brain signals is called as $\textbf{After taste}$ and the inability to capture the electrical signal from the tongue which has similar or lower Sweetness index is called as $\textbf{Sensory Fatigue}$ or $\textbf{Sensory Disruption}$ either ways the After taste is about the physical balance or when the sweeter taste is sweet so next thing is just below the level of it so it will taste "bitter" or not sweet as it has already known the interpretation of the sugar present in the previous sweet food. Sensory fatigue or Sensory disruption is disruptance or fatigueness of the sense organs making the signals less in number in order to identify it's Sweetness to the Brain for recognition and taste.

To alleviate or change the symptoms of "not being sweet" there is a need for drastic change to balance and clear the index for next sweet substance. How to do it??
To do this you need to defy the neural adaptation of something more sweet as the stimuli received (more sweetened substance) is often consistent and does not change. So by getting that we need something opposite of extreme sweet,,, that is,,, $\textbf{Extreme sourness}$ the intensified taste of a sour or bitter substance balances out the index and makes it back to "zero" this will make sure that next sweet thing you eat is actually "sweet" and not "bitter".

HOPE THIS HELPS AND GIVES YOU A VIEW OF SWEETNESS INDEX AND NEURAL ADAPTATION OF CONSTANT STIMULI!!!!!!