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News Release

December 05, 2006

U of G Prof Finds Way to Avoid Holiday Weight Gain

For many people, it’s difficult to avoid weight gain over the holiday season, but a University of Guelph professor has found that overweight adults who took a daily supplement of a common dietary fat lost weight and kept it off over the holidays.

In the new study published in the International Journal of Obesity, applied nutrition professor Andrea Buchholz and her colleagues at the University of Wisconsin-Madison gave half of their 40 overweight study participants a daily supplement of conjugated linoleic acid (CLA) for six months and the other half a placebo capsule.

“Despite no differences between the CLA and placebo group with regards to calorie intake or physical activity throughout the study, the CLA group still managed to lose weight prior to the holiday season and didn’t gain any weight over the holidays,” said Buchholz. “Within the placebo group, holiday weight change was significantly greater compared with the pre-holiday period.”

During the same holiday period (November and December), the CLA group lost weight and the placebo group gained 1.5 pounds of fat mass. “There’s evidence that you don’t lose that holiday weight, so that 1.5 pounds of fat mass would really add up year after year,” said Buchholz.

Even though both groups reported decreases in physical activity over the holidays, the CLA group still managed to reduce body fat mass.

Over the course of the study, the CLA group lost 2.2 pounds of fat. “That doesn’t sound like a lot, but that’s not just weight, that’s fat mass,” she said. “There was a tendency to lose it over the abdomen, which is even better because that’s the type of fat that’s really metabolically active and can put you at risk for heart disease.”

CLA is a naturally occurring form of linoleic acid (a type of polyunsaturated fat) that’s found in dairy products and meat. It has a molecular structure that gets metabolized differently from regular linoleic acid, said Buchholz. “Mice and other animals lose weight and body fat on CLA, but the human data weren’t consistent.”

There are different forms of CLA, and studies that mixed the two more common forms together showed the greatest promise, so the researchers decided to give their participants a mixed-form capsule of CLA.

This was the first study examining the effect of mixed-isomer CLA to use a four-compartment model to measure fat mass. This method combines underwater weighing, bone measurement, total-body water measurement and body weight. “It’s time-consuming and costly, but it’s one of the most accurate ways of measuring body fat,” said Buchholz.

The researchers also took blood samples at the beginning and end of the study to determine whether there were any risks from taking the supplementary form of CLA. “We looked at effects on liver function, inflammation and insulin resistance and found no adverse effects,” she said. “It looks as though there are very few risks in taking the mixed-form supplements (which can be found in pharmacies and health-food stores) and lots to be gained.”

An alternative to taking the supplementary form of CLA is getting the fatty acid from food sources, said Buchholz. “Many studies show that low-fat dairy products are helpful in maintaining low body weight, which can probably be partly attributed to the CLA.”