Cheek Packing

They usually pack cheeks because they are taking too much food in, or it's to big. There is also something known as a backward swallow where the tongue lays low and kind of does not do it's job. This interferes especially if baby does not like the food she's eating.
You may need to discuss with her pediatrician and he may suggest a speech therapist for the backward swallow.

While as others note, it is a phase some kids have, and you should not make a huge deal of it (if you do, it becomes more interesting to the child because it pushes your buttons) -- you SHOULD be sure that she empties her mouth before she leaves the table for one huge reason:

This is a big and obvious choking hazard. The descriptions other people posted about kids with hot dog or peanut butter in their mouths hours after eating gave me the chills -- both those foods are classic chokers for young kids. Especially the image of the child waking from a nap with food still in his mouth -- that's not funny, that's frightening.

Be sure she clears her mouth or don't let her leave the table.

We had this problem in spades. My son would down the first couple of bites, then store the rest for later. I can't even tell you how much my gag reflex was goin' when he woke up from a nap and began chewing on his stored-up hot dog. Ugh!
The truth is, for our family, there was nothing we could do to get him to stop. It was just a little quirky thing he'd do. We started swiping his cheeks a few times during his meals and continued to do it ... I'm going to say this stage lasted about six months. Freaky, I know. I honestly think it was just more thing he figured out his mouth could do. An extra toddler super power.
I would chalk it up to her age and swipe - especially at the end of the meal - and let her move on.
Good luck with this and your little chipmunk.

LOL! My son did this with bacon and with peanut butter. One morning on the way to work, I looked back to see that he was chewing. I checked and saw that he was chewing on his bacon from 45 minutes before. Reminded me of a cow chewing its cud!! I had to dig it out of his mouth!

The next time it was after his nap when I came in to get him. He had peanut butter all over his pillow and all in his hair. He had been "storing" it in his cheeks like the bacon! What a mess!

So yeah, you have to make sure that she has swallowed everything. It isn't really a matter of making her "not do it". It's a matter of getting her to finish her food before she leaves the table. It's just a "thing" and it doesn't mean anything. It's just the age.

Smiles!
Dawn

I am surprised some people think it a "cute" phase that will pass. It sound pretty dangerous to let your kid fall asleep with unchewed bits of food in their mouths. I'm no expert, though, well, maybe in common sense, but I digress...

I wouldn't sorry so much about stopping it, because it will then become a game. However, I would not let her up from the table until she either chewed AND swallowed the food, or spit it out.

Yep, my son used to do this. I honestly can't remember how long it lasted. I agree that it was more of a "look what I can do" than anything else.

We tried to just be aware of it and remind him at each meal to swallow his food. We also swept his cheeks if we thought there was something there. He got the idea after awhile.

Can't remember how long the phase lasted, but it most likely just a phase and nothing to worry about.

ETA - I noticed some of the posts mentioned this being a choking hazard and not something that should be taken lightly. I can't speak for other moms, but I never knowingly let my son do this. I caught him once, and my husband caught him another time. After that we were very vigilant.

This is not something I took lightly. Of course I realize it's a choking hazard. Letting another mom know that her child is doing something normal is not the same thing as saying this is not something that should be corrected. We realize this. Relax, people!

My daughter did this for a while. It drove me NUTS. She would sit there with the food in her mouth and wouldn't swallow it. I would get so irritated, because finally (of course) it tasted gross to her after sitting there for so long so she would spit it out. For us, I think it was primarily an issue of her just putting too much in her mouth at once, trying to finish quickly.

just wanted to suggest maybe going back to cutting it up into very small pieces. DH would hand our kids a plate with huge chucks of meat on it and i would have to point out to him that those bites were too big even for an adult like me. not that you are doign that, but maybe just go back to mincing it very fine.