The sports supplement industry is expected to be worth $730 million annually by 2018, but a new study suggests that men who overuse protein powders could be suffering from a form of eating disorder.

Dr. Richard Achiro and Dr. Peter Theodore led the research project and presented their findings earlier this week during the American Psychological Association’s annual convention. The two researchers surveyed 195 men between the ages of 18 and 65, all of whom used legal supplements such as whey protein and creatine, about a wide range of personal topics including supplement use, eating habits, and self-esteem.

They found that 40% of the participants had increased their supplement intake over time, while 22% routinely replaced entire meals with either whey powder or creatine. About 29% said they had become worried by their supplement use and 8% were actually advised to cut back by a medical professional.

Dr. Achiro explained to Fox News that while these body-conscious individuals may have obtained their ideal physique, protein powder overuse is similar to an eating disorder in that it can cause great harm both physically and in overall lifestyle.

“Even if they look good on the outside, do they have excessive diarrhea?" he said. "Are their livers and kidneys starting to give out from having to detox toxins? Are they adhering to this regimented style of eating in such a way to compromise their relationships and work life?”

Achiro suggested that more work needed to be done to address the psychological issues surrounding protein powder use because “it’s an underlying behavior men know is problematic, but are unable to change because so few of us men are open to addressing our emotional worlds and sense of inadequacy.”

Kidney damage is a commonly reported serious side effect from those who take far more than the recommended dosage of creatine, while whey protein can worsen both gout and kidney stones if the condition is already present.