How Natalie Portman beefed up for 'Thor' plus other intense celeb training routines

Natalie Portman is due to be on our big screens as the female Thor in Marvel's upcoming superhero film Thor: Love and Thunder – and she looks as strong as ever.

The actor, 40, is no longer just Jane Foster, the love interest of Thor, who she played in the 2011 and 2013, but has now evolved into the Mighty Thor.

With celebrities often undergoing strenuous workout routines for their roles – which of course they are lucky to have the funds, nutritionists and personal trainers to help them do safely – what did Portman's fitness journey to becoming a superhero look like?

Read more: How to start working out: A beginner's guide to getting fit for the first time

"It was really fun," she previously told Vanity Fair. "I worked with a trainer, Naomi Pendergast, for, I think it was, four months before shooting, and then obviously all the way through filming.

"We did a lot of weight training and a lot of protein shakes – heavyweight training that I haven't ever done before. Of course, I've never really aimed to get bulky.

"It was very physical, so it was a lot of both agility work and also strength work."

But how exactly does weight training help? "To build and maintain muscle, you need to place greater stress on the muscle tissue you already have with weights. Traditional steady-state cardio can't provide enough of an impact to achieve any appreciable muscle gains," PT and online fitness and nutrition coach, Daniel Harrod told Women's Health. Instead, workouts that put muscles under stress and stimulate new tissue growth are more effective.

Read more: 10 expert-approved weight loss tips good for your body and mind

Watch: Natalie Portman to show 'goofy' side in Thor: Love and Thunder

While Portman might not have done heavyweight training before, she's no stranger to transforming her body for a role, as she did for her role as a dancer in Black Swan.

"It definitely helps you get into character, and it's definitely changed the way I move," she also told Vanity Fair. "You walk differently; you feel different. I mean, it's so wild to feel strong for the first time in my life."

Showing her progression, she spoke about prepping for Thor in 2020 on The Tonight Show Starring Jimmy Fallon, admitting she dreaded the workouts.

When asked if she was doing any crazy exercises, she said, "I'm trying.

"I've had, months of, like, pandemic, you know, eating baked goods and lying in bed and feeling sorry for myself.

"So, I'm super tired after working out, and during, and dreading before."

Read more: Carol Vorderman, 61, breaks down her age-defying workout regime

She also discussed her diet and cooking videos on Instagram. "I'm vegan and a lot of people think we're eating alfalfa [a plant in the legume family] in the corner, so I like showing that there's really, delicious, varied, easy things you can do at home that your kids will eat that are plant-based. And I've been lucky to learn a lot from other people I admire."

Portman is among many other women who've successfully bulked up for roles.

Brie Larson

Brie Larson is no stranger to trying new workouts, regularly sharing updates on social media, including clips of her pole dancing, rowing, lifting weights and other intense and creative exercises.

This level of fitness was no doubt spurred on by her extensive training for her role as Captain Marvel, which she debuted in 2019.

"I started this journey thinking I'll get strong and I had no idea. I went far beyond what I ever believed was possible for my body," she told Insider earlier this year.

"Being able to hip thrust 400 pounds, deadlift 200 pounds, push my trainer's Jeep, I mean, it's an incredible experience to realise what's inside of you is well beyond what you knew was possible," Larson said. "And I have Carol [Carol Danvers/Captain Marvel] to thank for that."

After starring in Captain Marvel and Avengers: Endgame, Larson is due to appear again in The Marvels in February 2023.

While she can no longer pinpoint exactly how much time she spent working out for the film, because fitness is now an ongoing "huge part" of her life, she told the publication it still "definitely pushed me further".

Aware she wasn't necessarily going to break her deadlifting record or hip thrust record, she instead focused on "different goals" and "new challenges".

Her "main goal" was to be able to do a one-arm pull-up, which she was able to do on both arms after a few months of practicing. She then set out do a one-arm push up, which she also ticked off her list.

"I just started to get kind of obsessed with it," explained Larson. "When people say , 'Oh, girls can't do that,' it just makes me wanna do it even more. So there were huge accomplishments this time and I just feel like my body's just getting more and more used to this and more and more excited. Now, it feels weird to not train. I look forward to it."

Halle Berry

Halle Berry's training to be a MMA fighter in Bruised was so extreme, there's even now a new documentary showing all that went into it, Behind Bruised.

Her intensive training included learning five versions of mixed martial arts, including Brazilian jiu-jitsu, judo, Muay Thai, tae kwon do, and kickboxing, as well as upping her weight-training, reports Women's Health.

She even broke two ribs while shooting scenes, but kept filming. “I’m at my best when I have to work hard and when I’m facing challenges,” she said.

"To be the age I am and push my body to its limits reminded me that age is just a number. We can control how we define ourselves, and I've never been healthier and felt stronger."

Berry described working on the film as "totally empowering".

Read more: How much should we exercise? Only one in 20 adults getting it right

Margot Robbie

Many other celebs who have transformed their fitness for roles include Margot Robbie for Tonya Harding in I, Tonya, who trained for four hours a day, five days a week, for five months, learning to ice skate.

“I was honestly terrified that I wouldn’t be able to pull it off,” she told The Hollywood Reporter. “We were just a few weeks from shooting, and I was still struggling to find my outside edges. I just thought I was never going to get them, and then, one day, it just clicked.”

Gal Gadot

Gal Gadot did six months of training, with six hours of training every day – two in the gym, two for fight choreography and two horseback riding – for her lead role in Wonder Woman, she shared on Live with Kelly And Ryan.

Her trainer, Hayley Bradley, previously told InStyle said it was important to "balance each meal with equal amounts of protein and greens, and to be wary of seemingly healthy choices like green juice, which can be highly caloric thanks to the large amounts of natural sugars in some fruits and veggies".

Watch: Alicia Vikander adds climbing to exercise routine after Tomb Raider training

Blake Lively

For Blake Lively's role in The Shallows, as well as her workouts, her trainer Don Saladino told PEOPLE about the importance of her diet. "We made sure that her meals were well-balanced,” he said. “She had a protein, a vegetable and a slow-burning carb. We tried to give her enough so that she wasn’t stuffed, but she was comfortable.

“This is about feeding a woman who’s got a child who’s got to have certain nutrients in her body. She’s got to take care of herself. She’s got to eat healthy. The way that we did it was the right way, and it wasn’t through starving her.”

What to eat when you're training

The NHS Go website stresses the importance of carbs in exercise: "Carbohydrates, fat and protein all provide energy, but your muscles rely on carbohydrates as their main source of fuel when you exercise. Muscles have limited carbohydrate stores (glycogen) and need to be topped up regularly.

"A diet that is low in carbohydrates can lead to a lack of energy during exercise, early fatigue and delayed recovery."

It says while there's little scientific evidence that eating carbs at one specific time is better than another, it recommends basing meals around starchy carbohydrate foods and choosing higher fibre wholegrain varieties where possible.

When training, protein should also be included in most mealtimes to help with muscle building, such as beans, peas and lentils, cheese and yoghurt and milk, fish, eggs, tofu, tempeh and other plant-based alternatives, or lean cuts of meat or chicken.

A balanced diet also always includes plenty of fruit and veg – and you should make sure you're drinking enough water throughout the day (six to eight glasses).

Thor: Love and Thunder is due in cinemas on 8 July.