Chrissy Teigen gets fully nude for the cover of 'Women's Health UK'

Chrissy Teigen has never been shy about taking it off.

The 29-year-old supermodel goes fully nude for the cover of Women's Health UK's Naked Issue, wearing a big smile with her hands strategically placed over her breasts. But while Chrissy of course looks fantastic sans clothes, the always candid star admits her slim body takes work.

Women's Health

"I've always had to watch myself," Chrissy says. "My family is not naturally thin and we put on weight quickly. I find low-carb works for me. Even when I eat healthy grains like quinoa I keep them to a minimum."

WATCH: Chrissy Teigen Suffers a Wardrobe Malfunction of 'the Highest Caliber'

She also works out so she can eat "hearty dinners" and drink champagne, which, just by looking at her Instagram, her fans can see is not an exaggeration.

But Chrissy says her stomach has always been her "problem area." "I've never seen an ab -- ever -- no matter how many crunches I do," she admits.

And it turns out even gorgeous supermodels have body envy.

"I would love to have a little fat on my sides so I can be sexy, curvy," she shares. "I'd love a big butt. But I just can't get there."

Though despite some admitted body insecurities, Chrissy has zero problem getting naked -- in fact, she prefers it.

"The most uncomfortable I've ever been on set was having to model coats so I'm the most comfortable in my own skin, literally, just my own skin," Chrissy told W magazine last month. "I don't know what it is but sometimes I think pieces of clothing can be unflattering. Like there are certain things you can put me in where I won't look the same as that 5' 11" beauty, and sometimes I make really fashionable clothes look frumpy, and that's just my body type. That's just me, so I actually am better in less clothing. It's both a blessing and a curse."

And she especially loves getting naked with her husband, singer John Legend.

"We don't mind showing off our bodies -- we just feel like there's no problem being natural and nude when you're with the right photographer and it's done the right way," Legend told ET in March about their steamy DuJour magazine photoshoot.

Either way, it's safe to say Chrissy looks amazing with clothes or without.

Women's Health

PHOTOS: 27 Times Chrissy Teigen Was Almost TOO Real

Check out Chrissy's fight with Instagram to post a topless pic in the video below.