The weight loss market has grown rapidly in recent years, as people seek to lose weight for health and cosmetic reasons. One of the prominent factors associated with this rapid market growth is the rise of medical weight loss. In fact, the sales of GLP-1 prescription drugs helped the US weight loss market achieve an unprecedented milestone in 2023, reaching $90 billion. This marked a notable shift toward medical weight loss programs, as a growing number of physicians have begun incorporating weight loss into their recommendations.

The prominence of weight loss medications has also made itself a Hollywood hot topic, as some celebrities and actors in recent years have opened up about their use of semaglutides — a type of GLP-1 — like Ozempic and Wegovy.

About GLP-1 weight loss medications

But how does GLP-1 weight loss medication work? GLP-1, a glucagon-like peptide, is a gut hormone released by specialized cells in your intestinal tract after you eat. It does this by triggering extra insulin and by inhibiting glucagon, a hormone that raises blood sugar levels. 

Taking GLP-1 for weight loss can last up to 14 hours in your body, which is significantly longer than the GLP-1 that naturally occurs in the body (two to three minutes upon release). However, GLP-1 medications aren’t designed for people who only want to shed a few pounds. Doctors prescribe these drugs for people who meet certain criteria, like a BMI of 30 or more or 27 or more, for patients with weight-related complications such as hypertension or high cholesterol.

At the time of writing, there aren’t any known cases of celebrities or actors taking GLP-1 for weight loss to achieve a specific look for a film or TV role. Of course, actors aren’t strangers to undergoing drastic weight loss methods for their roles, some of which can be harmful to their health. Below, we’ll take a look at four actors who underwent drastic weight loss for their roles:

Cillian Murphy for Oppenheimer

In a previous post, we highlighted Irish actor Cillian Murphy’s Academy Award-winning performance in atomic historical narrative, Oppenheimer. The film, directed by Christopher Nolan, was yet another entry in the filmmaker’s list of technically excellent films, featuring authentic period details and a visually stunning depiction of the Trinity test.

On top of a stellar performance from Murphy, the actor also had to drop a few pounds to get the physicality and look of real-life physicist, J. Robert Oppenheimer. The actor described the weight loss journey as a miserable one following a very restrictive diet. Murphy has spoken about hating the feeling of going to bed hungry and always feeling cold, but acknowledged that it was as close as he could get to the real Oppenheimer, a man he described as one who “lived off cigarettes and pipes.”

Christian Bale for The Machinist

While not based on a true story, Christian Bale’s massive undertaking of losing 63 lbs in four months for his role in The Machinist has been a Hollywood hot topic for almost two decades since the film’s release in 2004.

Portraying an insomniac and troubled character, Bale underwent a diet that consisted of “practically nothing”, namely water, an apple, and one cup of coffee each day. Bale ate only 5% of the general standard 2,000 calories a day, something experts insist is harmful and can result in nutritional deficiencies, weakened bones, and a compromised immune system. The actor has since said that he won’t be doing any more extreme body transformations for the film.

Joaquin Phoenix for Joker

Another Oscar-winning actor known for fully immersing himself in his roles is Joaquin Phoenix. Having previously lost weight for his role in 2000’s Gladiator, the method actor was told by director Todd Phillips to lose some weight to play Joker.

To achieve the Joker’s deranged physicality and look, Phoenix worked alongside a doctor to ensure he wasn’t doing too many harmful things to his body in the process. The actor has stated he mainly relied on a calorie-restrictive diet to achieve his target weight but has spoken about a “strange” side effect to losing so much weight. Namely, a disorder-like obsession with losing or gaining weight once they had reached the required target.

Michael Fassbender for Hunger

Finally, in the aptly titled film Hunger by filmmaker Steve McQueen, Michael Fassbender plays Bobby Sands, a real-life Irish politician who went on a hunger strike while in prison. Understandably, the role required the actor to look a certain way. Like Phoenix for Joker, Fassbender relied on a low-calorie diet to lose weight.

The actor had a target of 127 lbs for the role, which he had achieved over a 10-week period. Fassbender limited himself to 1,000 calories a day and then dropped his caloric intake to 600 calories per day, a diet consisting of a tin of sardines, berries, and a handful of nuts daily. Like others in this list, Fassbender has openly stated he would not be willing to do what he did for Hunger again.

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