WITH CHILDHOOD obesity rates finally peaking, I'm not sure now is the time for a hero who saves the day by being fat, but that's "Kung Fu Panda." In a nutshell.

It's a China-set, animated action/comedy with roly-poly Jack Black as the voice of Po, a chubby restaurant worker whom the village wise men improbably designate as the warrior chosen to defend their homes against the prophesied return of a fearsome fighter (Ian McShane).

The elders send Po to a kung-fu temple for special training under a Yoda-like mentor named Shifu (voice of Dustin Hoffman), but the running joke is that clumsy, hungry Po can't stop eating or clowning long enough to complete his training.

The movie's early moments are flat and predictable, and even 30 minutes in, you may find yourself ready to curl up in your seat for a long summer's nap.

"Kung Fu Panda" flickers to life, though, when its villain finally emerges - an unbeatable and uncontrollable warrior, once Shifu's prized pupil, who escapes from jail and returns to punish the village for his rejection and incarceration.

In the meantime, Po manages to repair relationships with the more talented kung fu pupils (Angelina Jolie, Lucy Liu) who were displaced when he was inexplicably installed as savior.

Po wins friends through the sheer force of his simple, likeable personality (and his noodles), and even his kung fu improves when Shifu realizes that Po will do anything for a cookie.

A hero whose power is gluttony? I almost missed this part, because I was out in the lobby getting a bucket of popcorn and a 40-ounce soda, so I'll refrain from comment. Anyway, super-sized Po faces his foe with a new self-confidence, leading to an extended action finale.

This ups the tempo, although the movie probably spends too much time imitating wire-fighting stunts of Pacific Rim martial-arts movies. These are amazing in live-action, not so hard to believe in an animated context.

On the subject of live action, the movie's stories and themes are similar to those of the recent live-action "Forbidden Kingdom," a fun, clever and underrated movie that came and went with a low profile.

"Panda" isn't as consistently good, but, like Po, it has boundless energy, and is insistently eager to please. It might succeed with in doing so with younger kids.