I'll preface this with, I have no medical training

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My DD was diagnosed with hypoglycemia and I was concerned about her having enough food and energy to make it through a 4 hour practice. Her pediatrician reccomended Carnation Breakfast Essentials (used to be Carnation instant breakfast).
It has a good ratio of carbs to protein, and keeps her feeling good for hours.
We do not use it as a meal replacement, but as a snack or a drink with breakfast.
It has 5g of protein as the powder and depending on the type of milk you buy, as much as 15g mixed. Lots of vitamins and minerals too. It also comes in lots of flavors and a sugar-free version.
Since she is so tiny, I would suggest starting with half a glass and seeing how that goes before having her drink the whole thing. My 6 & 7 year old share one and I use soy milk for them.
Adult protein shakes and bars are made for people 3 times her size, so I would advise against those.
Cliff kids bars are good as a snack too, less protein and organic.
Since she has no medical problems, adding a glass of milk each day, a couple of extra eggs a week or some nuts as asnack are good ways to boost her natural protein consumption.
Good luck!
ETA... Just read Bog's post, sorry to repeat what she said
