Gwyneth Paltrow: My Clean Diet "Changed My Marriage" to Chris Martin

Gwyneth Paltrow's low-carb, gluten-free diet hasn't just affected her children, Apple and Moses. Covering the April issue of self, the 40-year-old actress says her clean eating has impacted her nearly 10-year marriage to Coldplay frontman Chris Martin, 36.

"You feel lighter and your emotions get smoother," the It's All Good cookbook author says of her healthy diet. Adding that she often felt "run-down" before changing her eating habits, Paltrow says she "had a lot of unexpressed anger. I made everyone else's feelings more important than my own. I'd suck it up and then be alone in my car yelling at traffic or fighting with hangers in my closet when they got stuck together."

The Oscar winner continues, "You're not learning anything unless you're having the difficult conversations. Dealing with things directly changed my relationships. Sometimes when you get clear about who you are, others get less comfortable because they liked who you were. It's changed my marriage, too, but he's up for the challenge."

According to Paltrow, it wasn't until "a couple of years ago" that she realized how much her diet affects her mental state. "I had to sing at awards shows, which was fun but stressful. I'd have a Guinness and a beta-blocker every time. I also was constantly getting on airplanes, trying to knock myself out with sleeping pills and wine, waking up, trying to sweat it out with exercise and a steam, and then working really hard all day. Eventually, I had a panic attack," she recalls. "My body was like, 'What is happening?'"

"My doctor, Alejandro Junger, recommended that I cut out basically everything: dairy, sugar, gluten, anything processed. I was like, 'What the f-ck am I going to eat now?'" the Country Strong star remembers. "That's why I made the book: to stop eating brown rice out of the fridge because I didn't know what else to eat -- it was demoralizing."

Paltrow, who released her first cookbook in April 2011, insists that her diet isn't as restrictive as it sounds. "I probably eat this way two or three times a year for three weeks at a time. Past that, I'm not willing to make the sacrifice. Life is about balance," she explains to self. "It's good to work in healthy food, whether it's five days a week or five meals a week. And if you're going to do it, it should be awesome food you're psyched to make. But never cut out the brownies or the wine."

These days, instead of reaching for a Guinness and a beta-blocker, the Glee guest star has found another way to unwind. "I watch Homeland or New Girl. I also like to have martinis with my girlfriends. I feel a sisterhood emerging around me," says Paltrow, whose close friends include Beyonce and Cameron Diaz. "I'm less threatening now that I'm 40 and not 26-with-an-Oscar. There's a sense of love and support. I feel really lucky."