Credit: Gustavo Caballero/Getty Images

Leonardo DiCaprio's supermodel girlfriend has one of the hottest bodies in the biz, but even Erin Heatherton needs to watch what she eats.

"I love apples and almond butter, but I think it's making me fat right now," Heatherton, 23, told Us Weekly at the Victoria's Secret Very Sexy Pushup launch event in NYC's Herald Square store Tuesday. "But I just love almond butter!"

If Heatherton's favorite snack is indeed wreaking havoc on her waistline, it certainly doesn't show.

"I just started this class, Pure Barre, which is so awesome and hard. It's inspired me to change up my workout," Heatherton said. "I used to only really do yoga, because I feel yoga is important for everyone -- it really calms me down and it's important to stay flexible."

She added: "Even if you don't have time for a big workout, stretching in the morning and night really changes your body."

Heatherton, who said she doesn't "emotionally eat," recently went rock climbing with DiCaprio, 37. "I always stay active, even if I'm on vacation," she told Us. "At home I don't like to be just sitting around; I like to go out and do things. It's when I'm the happiest."