Can a stomach physically shrink over time when someone eats less food?

yes and no

your stomache grows and shrinks everyday

when it is empty it is like a deflated ballon and about the size of a fist

it is a muscle,

when you eat it increased in size by expanding to allow space for whatever it is you are eating

im assuming you mean can you cause your stomach to actually shrink beyond its minimum deflated state by not eating as much,

then the answer to this is no you can not

you may feel like your stomach shrinks over time as you feel full off less but this is not actually your stomach being smaller more your body being more in tune with your lifestyle

the more you force your body to eat the more it will adapt to take it

Yes, it does, the best way is to fast for 3 days, it gets about as small as a cup, then from there you can control what you eat easier, as soon as you feel full stop eating, you can lose weight like that.

yes it does, that's why the healthiest way to eat is small meal whenever you feel hungry.

Yes it does..