Big eyes, empty bellies

I often wonder how either of my children manages to grow. The beautiful wife and I put food on their plates and more often than not throw away just as much as we served them.
But they continue to grow like weeds.
Little sister just keeps getting taller and is starting to get hard to carry around. (Which is all right because she would rather walk anyway.)
Big sister needs new shoes and clothes every three to four months as quickly as she shoots up.
We've tried a lot of things to get them to clean their plates.
-- Had them help fix the food: big sister loves to cook, but is just plain unadventurous when it comes to eating.
-- Let them pick their meals: They still just pick and we end up just spending a lot of extra time making their food because we still want to eat things with taste. Hotdogs and hambugers for every meal is just plain boring.
-- Tell them they can't get up until the food is gone: they just sit there and play and whine around until we just give up and put them to bed.

Recently we let Little sister dish her own food, not really because we thought she would eat it, but because we weren't watching. Next thing you know her plate is heaping.

She played around for a while, gabbed at her sister, watched some Spongebob and then walked away to do something else. Her plate looked like this when she was done.

And yes, the two photos really were taken at two different times.
I'm not sure when or what, but they must be eating, because, as I said, they keep growing like weeds.