Credit: Jason LaVeris/FilmMagic

It's safe to say Gwyneth Paltrow is nothing short of a lifestyle expert, but she has no problem showing that she is far from invincible from the challenges that aging can bring.

The Oscar winner continued to prove just that as she dished on how her body changed after she turned 40, revealing that her energy level and relationship with food shifted significantly once she hit the milestone. "I thought, 'I eat well, I sleep, I exercise—so why am I always so tired? I don't get it," the now 44-year-old Paltrow told People.

The Goop founder noticed the biggest change in her body whenever she indulged in comfort food, noting how her physique was affected in a new way by her diet choices. "It's really incredible," she said as she described how her metabolism slowed down in her forties. "People warn you that it's going to happen."

"I was always like, sure I'll eat a cheeseburger and fries and it just won't stick," she continued. "And then after 40 that completely changed."

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After Paltrow kept hearing other women have similar complaints, she decided to do something about it. This month, she launched Goop Wellness—a collection of four different vitamin packs developed by physicians she swears by. To combat her own fatigue, Paltrow takes the "Why Am I So Effing Tired" pack, which fights exhaustion.

In addition to her supplemental vitamins, the busy actress has also made dietary changes to make sure she stays alert, curbing her sugar cravings and not indulging in fried food as often. "I think as I've gotten older and hopefully wiser I've tried to focus on doing little things throughout my week to bolster my strength and energy," she continued.

"I'm trying not to cave into sugar cravings and lots of white carbs all the time, because that's my kind of go-to; if I get tired in the afternoon I want pretzels, or I want Swiss cheese on a cracker or a baguette. I really love white carbs, which is not great for optimizing your health and your energy."

As for the fried grub, Paltrow said, "I've had to become more mindful about just in general when I'm having fried food just knowing that, 'OK, that may stick in a way that it didn't used to 20 years ago."

Still, it's not something she's willing to completely do without. "By the way, I'll never give up fried foods," she added. Fried octopus aside, naturally.