Kevin Federline Hospitalized During Weight Loss Reality Show

Kevin Federline was hospitalized in Australia last month after over-heating during production of a weight loss reality show called "Excess Baggage" ... a rep for the show has confirmed.

According to the rep, K-Fed was participating in a segment in a part of the Outback that's known to get VERY hot ... when the show's medic deemed he was "showing signs of heat stress."

Federline was taken to a nearby hospital and treated -- but he eventually returned to the show ... which is still in production.

You'll remember ... a hefty K-Fed was spotted jogging around Los Angeles last month (see above and below) ... and he didn't look like a guy who could withstand exercise in extreme heat.