Woman lying on bed(Photo: Courtesy of Men's Health)

Are your frenemies giving you cancer? It's possible. According to a new UCLA study, bad friends are bad for your health.

Researchers asked 122 healthy adults to keep a diary of social interactions for 8 days. Their findings? Those with negative social experiences had a higher level of inflammatory proteins that can lead to heart disease, depression, and cancer when compared to than those who noted fewer negative experiences.

More from Men's Health:19 Temptaions You Should Resist...Or Indulge

"We think our bodies construe negative social interactions as stressors which create higher levels of harmful inflammatory proteins," says Jessica Chiang, lead researcher, and graduate student at UCLA.

The solution is easy: Cut out toxic people in your life. "Purging these relationships from your life could lower levels of these harmful proteins," Chiang says. Here are three friends you must deal with:

The Fighter

This guy picks to fight every battle -- and you've gotten used to it. Constantly bickering with people can lead to an increase in cortisol, which suppresses the inflammatory processes and inhibits the creation of proinflammatory proteins, the study found. And if you're wondering: Find out why on Earth he's so angry.

The Competitor

There's nothing wrong with a little healthy competition -- it keeps you in check. But the guy you run with on the weekends who's constantly one-upping you, and your work buddy who's always sucking up to your clients? Make some distance. Both leisure and work competition elicit high levels of inflammatory proteins.

The Woman Playing Hard to Get

That girl who only sometimes answers your texts has to go, too. The study found that vying for a romantic partner's attention had similar negative consequences.

The Yes-Man Who Never Does Anything

Surprisingly, stress can come from pretty small things that add up over time -- like your friend who swears he'll give you that 10 bucks/buy the beer next time/pick you up, but you know he's not going to. If you feel like you're overcompensating in a friendship, you probably are.

So how do you break up with a friend? If you've hit your limit and could care less about salvaging the friendship, let it fade. Scale back emails. Take him out of your call rotation. He'll get the point.

Think there might be hope? Keep the conversation short. If you deliver an uppercut at the start and not the end, you'll be about 35 percent more persuasive.(And if you need an exit strategy, check out our list of ideas.)

Video: Little Changes Make Positive Thinking Possible >