Pot-smokers, beware: You may want to avoid dieting before that next company drug test. New research shows that even if a person hasn’t smoked marijuana in months, he or she could still test positive for the drug after dieting or beginning a heavy exercise ritual. In a recent study using rats, Australian scientists found that extreme stress or major dieting can result in a positive drug test, even if the tester hasn’t smoked pot in weeks. Fat cells love the psychoactive ingredient, Tetrahydrocannabinol (THC), found in pot, and they absorb it—and hold onto it—extremely well. Even long after a person stops smoking up, his body undergoes changes as a result of exercising or shedding pounds, and these changes can cause THC to be released into the blood stream once those fat cells start to break down. New Scientist reports:

Jonathon Arnold and colleague Iain McGregor first exposed THC-laden fat cells taken from rats to the stress hormone ACTH. They found that the hormone increased the speed of release of THC from the cells. Then they injected rats with 10 milligrams per kilogram of THC (equivalent to a person smoking between five and 10 cannabis cigarettes, depending on their strength) every day for 10 days. Two days later, they injected a third of the rats with ACTH, deprived another third of food for 24 hours, with the rest as controls.

Blood tests showed that the rats who where on diets had twice as much THC in their systems—though the effects only lasted for two days. The scientists will have to test out their theory over a longer time scale, but the true test will be whether humans show identical effects. And it can’t come too soon: In this economy, you don’t want anything to get in the way of your employment. Related Content: Discoblog: Pot In A Pill? Discoblog: World's Oldest Stash

Image: flickr/ BodhiSativa Photography