Husband Marc Anthony spilled the news to Extra.

"Jennifer is training for a triathlon, in October," Marc said, keeping a straight face. There is no way a woman who has that much packed into a bikini will finish a triathlon.

Is this because her restaurant closed? Her favorite available food source was taken away and she wants a fresh start?

And who's watching the kids since they don't use nannies?

"I'm very supportive," says her emaciated husband. "I'll be on my Segway [encouraging her]."

He'd better watch his ass. Jenny will be taking over that Segway after the first 1/2 mile, and running him over with it.

Divas. Can't. Get. Sweaty.