Boxer Mike Lee fights for a world title Saturday after an autoimmune disorder kept him out the ring for nearly two years. Here's the evidence behind his unconventional training.

Mike Stobe/Getty Images World-class fighter Mike Lee uses a variety of complementary wellness techniques to stay in a top physical and mental form for his fights, including his upcoming title bout against reigning champ Caleb Plant.

Lee has ankylosing spondylitis, a chronic autoimmune disorder, which he manages through nutrition, CBD, heat, and cold therapies.

He also uses meditation and visualization before his fights to prepare for peak performance.

Some of his strategies, like meditation, are supported in the scientific community. Others, like CBD, are more controversial.

Visit INSIDER's homepage for more. Financier-turned-pro-boxer Mike Lee will put his 21-0 undefeated record to the test on Saturday as he takes on the current world middleweight champion Caleb Plant. Until now, one of Lee's biggest fights has been outside the ring - he lives with a chronic autoimmune disorder called ankylosing spondylitis, which he was diagnosed with in 2014. Before that, he suffered years of pain with no apparent cause that was so excruciating it kept him from competing. Read more: A sports psychologist shares the visualization technique that's helped Super Bowl champions and Olympic gold-medalists Lee says the illness has helped him fine-tune his eating and other lifestyle habits to make him healthier and more competitive, both in and out of the ring. Here are some of the strategies he swears by, and the evidence behind them.

Lee uses visualization to experience every aspect of the fight before he steps in the ring. Edward Diller/Getty Images Before every fight, Lee uses all five senses to imagine every aspect of what will happen, from the sound of the crowds to the smell and taste of sweat (or even blood). He said this helps him feel confident and relaxed, and ready to perform. "When I step in the ring, it's like I've already done it 100 times," he told Rich Roll in a podcast. Sport psychologists have promoted visualization, also called positive imagery, as a success strategy for decades and studies show athletes who use visualization techniques can improve scores or game outcomes.

Boxing puts the body in fight-or-flight mode. Meditation helps bring it back to a rest-and-digest state. Flickr/Go To Take Back Your Health Conference Lee has said meditation also calms his nerves. He regularly spends a few minutes with a meditation app to center his mind. Research shows that improved self-confidence and focus after meditation can boost athletes' performance. It seems to work by helping to reduce inflammation, which is especially important for managing autoimmune condition's like Lee's.

Lee uses a simple breathing technique to reduce tension. Shutterstock Lee also uses a system of breathing called 4-7-8, which means inhaling for four seconds, holding the breath for seven seconds, and then exhaling audibly for eight seconds, he told Roll. "I do it in the dressing room and my heart rate just drops," he said. This kind of breathing, which was developed by Dr. Andrew Weil, is known to reduce tension and anxiety, and convince the body to relax.

CBD is Lee's go-to treatment for everything from pain and inflammation to anxiety. ElRoi/Shutterstock Lee endorses cannabidiol, or CBD, a substance derived from cannabis, but without the psychoactive properties. He told Roll the substance helps relieve some of the pain and anxiety associated with his disease. Lee also co-founded his own CBD company called Soul CBD, which aims to help people manage pain, quell anxiety, or boost muscle recovery. The brand contains no THC, the chemical in marijuana that causes the high, so athletes who undergo drug testing can use it. Early research suggests CBD may have a myriad of benefits, including relieving pain, stress, and inflammation, but more research is needed to understand its long-term effects and interactions with other drugs and supplements. Additionally, the CBD market in the U.S. is largely unregulated, making it difficult to be sure you're getting what you paid for.

Lee's diet leaves out gluten, dairy, eggs, and anything artificial. AlexRaths/ iStock During his illness, Lee tried various elimination diets to see if anything he was eating might be contributing to his health woes, he told Roll. He said he now feels his best when avoiding gluten, dairy, eggs, and all artificial foods, according to an interview with The Manual. Evidence shows that eating a balanced diet, whether or not it includes certain food groups like gluten or dairy, has health benefits. Any nutritional plan that includes more veggies and high-quality protein, and less sugar and junk food, can be good for you, research suggests. And avoiding processed foods has been shown to help people live longer, healthier lives.