President Obama, 48, passed his exam...

President Obama, 48, passed his physical exam Sunday, though the results show he should watch his diet and keep up his efforts to quit smoking.

"The president is in excellent health and 'fit for duty,' " said a report from Jeffrey Kuhlman, the president's doctor. "All clinical data indicate that he will remain so for the duration of his presidency."

Obama underwent his first physical as president at the National Naval Medical Center in Bethesda, Md. Kuhlman said the president could wait until he's 50 (in 2011) for his next physical. After the 90-minute exam, Obama visited with wounded soldiers who are being treated at the facility.

Kuhlman recommended changes to Obama's diet to reduce his cholesterol level and urged him to "continue smoking cessation efforts." Last June, Obama acknowledged he had sometimes "fallen off the wagon" and occasionally still smoked, despite efforts to quit.

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The president is "doing the right things," says Cam Patterson, a cardiologist and professor at the University of North Carolina-Chapel Hill. "The stress of being president hasn't made his weight go up."

Obama's weight, blood pressure and resting heart rate are all much lower than average, suggesting he is very physically fit and is exercising regularly, Patterson said. He estimates that the president is in the top 25% of men his age in terms of health.

"That doesn't mean he's without risk," Patterson said. "It means he's taking care of himself."

Obama does have several factors for heart disease, including being a man, a history of smoking and moderately high "bad cholesterol," or LDL, Patterson said. If this number continues to rise, Patterson said, Obama's doctor might consider prescribing drugs to lower his cholesterol, known as statins.

Screening tests for prostate cancer and colorectal cancer found nothing suspicious, the medical report said. Obama's mother and grandmother died of cancer.