It turns out a Syrian’s cheek pouches extends all the way to the hips and that’s how they’re able to pack so much away.
Here’s another video of one pouching way too many carrots:
Dwarf hamsters can do it but obviously due to their size difference, they won’t be able to get as much in. Here’s one of a Russian dwarf hoarding some sunflower seeds:
And this is not quite related but I feel obligated to include a video of Ichigo, my Roborovski hamster cracking open a lot of sunflower seeds he stored in his pouch.