Just a day ahead of Macworld's keynote, Steve Jobs has revealed he is suffering from a "nutritional problem". After months of speculation about the Apple CEO's health, the man himself has made a statement.

"I have been losing weight throughout 2008. The reason has been a mystery to me and my doctors. After further testing, my doctors think they have found the cause - a hormone imbalance that has been 'robbing' me of the proteins my body needs to be healthy".

"The remedy for this nutritional problem is relatively simple and straightforward", Jobs said as he announced plans to stay on as Apple CEO during his treatment that's expected to last until late spring.

"I will be the first one to step up and tell our board of directors if I can no longer continue to fulfil my duties".

The Apple board also released a statement: "Apple is very lucky to have Steve as its leader and CEO, and he deserves our complete and unwavering support during his recuperation. He most certainly has that from Apple and its Board".

UPDATE: Steve Jobs' letter has been revealed in full - see link below for the entire text.