Earlier today, for the weight loss that had sparked speculation about his health since last June, when he appeared at Apple's annual developer's conference looking gaunt. Much of the talk about his appearance, and concern by investors about his condition, centered around the possibility that he again had cancer.

In August 2004, Jobs, who is 53, announced he had had surgery to remove a cancerous neuroendocrine tumor in his pancreas.

According to , the director of the Carcinoid and Neuroendocrine Tumor Center at Cedars-Sinai Medical Center in Los Angeles, there are two likely explanations for Jobs' weight loss.

"A lot of this is speculative," Yu said to preface his reasoning, "since I don't know Mr. Jobs' condition specifically. But in terms of weight loss, and if the tumor was completely removed, it would be likely that he would have secondary Type 1-like diabetes. That's very common with patients who have had a large chunk of their pancreas removed," said Yu. "I see that very commonly."

When patients have surgery similar to Jobs', surgeons may have to remove many of the "beta cells," the type of cell in the pancreas that produces and releases insulin, along with the portion of the pancreas. "When you remove a large chunk of the pancreas, you often have insufficient insulin," said Yu. "I would think that [Jobs] has Type 1-like diabetes."