My "foot-twitches-so-hard-it-shakes-the-car" wife will be happy to learn she's actually got a healthy habit:

Overweight people have a tendency to sit, while lean ones have trouble holding still and spend two hours more a day on their feet, pacing around and fidgeting, according to researchers whose findings were published on Friday.

Which also proves children work from a different metabolic table, otherwise Olivia would be the thinnest child on the planet.