The energy you burn during exercise may be less than you think. For example, an average 30-minute bout on the treadmill for most people only burns about 250-300 kcal or kilocalories, a measurement of energy—the same amount found in just one bagel. An additional way to burn more calories is to enhance energy expenditure at other times of the day, such as at nighttime when you are asleep.
A recent study tested whether conjugated linoleic acid (CLA), which has been shown to promote fat loss, could affect resting energy expenditure and fat burning during sleep. Subjects were provided either a placebo or CLA (3.2 grams per day) for 6 months. Before and after supplementation, subjects were studied in a room that measured the total calories and fat calories they burned during a 24-hour period. Total energy expended while sleeping was 43 kcal more in the CLA group compared to placebo. The CLA group also burned 99 more kcal of fat while sleeping than placebo.
These results indicate that CLA reduces body fat by increasing energy expenditure and fat oxidation during sleep.
Reference: Am J Clin Nutr. 2007;86(3):797-804.