Overweight adults who took conjugated linoleic acid (CLA) burned more calories from body fat while sleeping, in a new study.
Researchers from the University of Wisconsin at Madison, recruited 23 otherwise healthy but overweight men and women with a body mass index (BMI) of 25 to 30, aged 18 to 44, to take 3.2 grams of CLA per day at breakfast or a placebo for six months. To accurately measure how much and what types of energy participants burned, doctors placed each man and woman inside a special sealed monitoring room called a metabolic chamber for 24 hours at the start and end of the study.
After six months, those who had taken CLA burned an average of 4 grams more body fat while asleep than they had at the start of the study, while those in the placebo group burned 7 grams less. Those in the CLA group also burned 3.3% less energy from protein while asleep compared to the start of the study, while the placebo group burned 0.3% more. Compared to the start of the study, the placebo group burned an average of 43 fewer calories while asleep, while there was no change in the CLA group.
Doctors noted that those who took CLA also burned more body fat while awake, but that this result was not statistically significant. This is one of the first studies to measure over a 24-hour period how CLA burns fat. Earlier studies measured shorter periods of time, did not use a metabolic chamber and did not monitor sleeping hours. Doctors said the study confirmed that CLA burns body fat rather than fat from the diet.