Re: 11 month old....INSATIABLE!
Have you looked into baby led solids? She might find it more satisfying than jar food. But it sounds like she's hungry. I don't think at this point you need to introduce formula though. Perhaps just offering more food, more often. Also, it sounds like you aren't consuming enough calories. I did that with my first child. You need to be sure that you're eating enough and drinking enough or she will get all of her nutrition from you, meaning you won't be getting it.
If you obey all the rules, you miss all the fun. - Katharine Hepburn