So just what is her secret?
The award-winning actress is known for following a healthy, well-balanced diet – but doesn’t follow any strict rules.
“I love a good cookie,” she told People. And unlike most of her keto-loving peers, Julia is also a fan of pasta.
“Why is everybody scared of pasta? Pasta never did anything to you,” she laughed. “Don’t be mean to pasta.”
In fact, Julia prefers not to follow a low-carb plan and when she was required to lose a fair bit of weight for a recent role, she enlisted the help of nutritionist Carrie Wiatt, who incorporates carbs into her eating plans including Julia’s favourite, mashed potatoes and bread.
“I played a role that required I lose considerable weight,” Julia told The Independent (Ireland).
“Carrie helped me lose over 43 pounds [20 kilos] quickly, safely, and with a minimum loss of sanity with her common sense-approach diet,” she added, explaining that she wanted a plan that would keep her energy levels up, while still helping her to shed the kilos.
At home, Julia always makes time to eat with her family. "We definitely try to eat mindfully," she told InStyle.
"As I always say to my kids, 'You have to eat the good stuff to get the good stuff.' We love that philosophy!"
Another key to Julia’s youthful exterior is doing everything in moderation. She told the publication that a strict diet would drive her mad. I would just go crazy. So I think, better just to remain calm, drink your water, get your sleep and be joyful.”
The mum-of-three is also equally laid-back about getting older and is willing to take everything in her stride.
“[I’m] trying to have some peace with the ageing process. Just realising that it’s going to happen whether I like it or not,” Julia told Viva.
When it comes to her beauty routine, the actress keeps it simple. “On a regular day, I’ll just brush my teeth, wash my face and apply sunblock,” she told the publication.
“I’m a busy mum, and sometimes I just sunblock my kids and run outside and get my nose burned. So I’ve made a stronger effort to take care of myself.”
Julia is known to be a fan of Pilates and water workouts. She’s also trained with Kathy Kaehler for her role in America’s Sweethearts, who sculpted her body through yoga and Pilates.
“Exercising with Kathy has changed my life in a great, subtle and consistent way,” says Julia. “I don’t love exercise, but I do love how I feel afterwards. Accomplishment, clarity, energy, strength, joy ... these are all things I give myself through working out, and I can feel it in everything I do."