It's no secret that Nicole Richie has been in a constant battle with her health.

But on Wednesday her rep revealed to People magazine the newly discovered reasons behind her fatigue: she suffers from hypoglycemia, which occurs when your blood sugar levels drop too low to provide enough energy for your body's activities.

As Richie gears up for the fifth season of "The Simple Life," where she and Paris Hilton will be counselors at a health camp, it's been her own health taking the center stage.

"Four or five times she's felt really faint and almost passed out," an inside source told People.

"In her ongoing effort to focus on her well-being, Nicole has recently been diagnosed with hypoglycemia," says her rep. "[She] is taking steps to manage it."

Source