FRESNO, Calif. (ABC 30) — People looking to bulk up may want to consider cutting back on protein shakes.

New research from the University of Sydney suggests that protein shakes may lead to weight gain, depression and shorter life spans.

Scientists involved with the study say the branched-chain amino acids found in many protein powders can stay in the bloodstream and disrupt serotonin production in the brain.

Serotonin not only helps to regulate moods, but also helps control appetite.

This story is courtesy of our ABC affiliate, ABC 30 in Fresno.