SEATTLE -- So what will it be -- butter or margarine? Butter has saturated fat. Some margarine has unhealthy trans fats.

Here's how Dr. John Swartzberg at the UC Berkeley Wellness Letter answers that question:

"You shouldn't use a lot of margarine. You shouldn't use a lot of butter," he said. "If you're going to use a little bit of butter or margarine, don't worry about it. I wouldn't even worry if it's butter or margarine if you're just using a little bit."

For those who prefer margarine, the Wellness Letter has this advice: Skip the sticks and choose a tub or squeeze spread -- preferably made from liquid vegetable oils.

"In general," Dr. Swartzberg says, "the more solid the margarine, the more trans fat it has.

"But also look on the label to see if there are trans fats in there and if there are try to avoid that particular margarine."

Something else to consider: the Wellness Letter points out that regular margarines have as many calories and as much fat as butter - 100 calories and 11 grams of fat per tablespoon. That's another reason for moderation, no matter which way you go.