"I don't believe in diet. I feel like if you want to eat a hamburger or pizza or Spanish jamón, you should just do it," she exclusively told ET's Carly Steel at the Pronovias bridal show in Barcelona, Spain, on Monday.
Irina Shayk Shows Off Impossibly Flat Tummy Less Than a Month After Giving Birth
"This is the secret. Just enjoy your life, and [knowing the] balance between eating and working out always helps," she added.
While Shayk and Cooper are notoriously private about their personal lives, it's clear the two couldn't be happier, two years after sparking engagement rumors.
The model stayed mum on possible wedding plans, but she couldn't help but gush about some of the Pronovias designs featured on the runway. "My style is really simple, and less is more, so I definitely like this, because it has a little detail," she explained. "I like the long sleeve. It's really classy and voila, an open back."
It's not hard to please Shayk -- "Just sometimes a little card and a little note can be romantic," she said -- but when it comes to giving gifts, she goes all out. The Victoria's Secret Angel treated Chrissy Teigen's daughter, Luna, with a toy convertible for her second birthday earlier this month.
"When I was thinking about the present, I was like, 'What can a Russian girl give to a little girl?' And I was like, 'We have to go all the way,' and that was Mercedes," she shared. "I guess Luna loved the present, and that's all that matters."