...but fat by any other name is just fat.

Health food stores across the country sell medium-chain triglyceride (MCT) oils as a quick energy source for body builders and a less fattening fat for dieters. Enthusiasts claim, with support from some scientists, that because MCT oils are digested differently from larger triglycerides like those in palm oil, they don't raise blood concentrations of cholesterol.

But a new study by researchers from the University of Texas Southwestern Medical Center at Dallas lays waste to such claims. The researchers studied nine middle-aged men who agreed to live at the hospital while being fed a controlled diet containing either palm oil (which increases blood lipids), sunflower oil (which doesn't increase lipids), or MCT oil. After 3 weeks, the researchers measured the volunteers' cholesterol and triglyceride concentrations, then switched the diets. After 12 weeks, all participants had tried all three oils.

Not surprisingly, sunflower oil had no ill effects, and palm oil raised cholesterol and triglyceride concentrations. But MCT oil raised these lipid concentrations just as much as the palm oil.

From measurements of the types of lipids in the men's blood, the team speculates that enzymes in the liver use MCT as building blocks to make the troublesome component of palm oil, says study investigator Nilo B. Cater.