Not a workout hack or crash diet: Matt Damon reveals the one thing he cut from his diet to drop over 13 kg for his Odysseus transformation

Hollywood transformations often fuel diet trends, but Matt Damon’s latest physical overhaul for Christopher Nolan’s upcoming epic has sparked a more nuanced conversation about discipline, medical guidance and what weight loss really involves.

Matt Damon’s Odysseus transformation draws attention

Actor Matt Damon has revealed that eliminating gluten from his diet played a key role in shedding over 13 kg for his role as Odysseus in Christopher Nolan’s highly anticipated film The Odyssey. Speaking on the New Heights podcast hosted by Jason and Travis Kelce on January 7, the 55 year old actor described the intense physical preparation required to meet Nolan’s vision of a lean yet powerful Greek hero.

Early images from the film circulating online prompted Jason Kelce to remark on Damon’s noticeably muscular appearance. The actor responded by confirming he had lost significant weight while training extensively for the role.

A director’s vision and a disciplined routine

Damon explained that Nolan wanted Odysseus to appear agile and strong rather than bulky. That requirement shaped both his training and nutrition. He likened the preparation to an athlete’s season, saying that once the routine begins, physical conditioning becomes an essential part of the job.

To meet those demands, Damon said he adopted a strict diet alongside regular training. One key change was removing gluten, a decision that also aligned with a separate medical discussion he was having with his doctor.

Cutting gluten and dropping to a “high school” weight

On the podcast, Damon revealed that he stopped eating gluten during the film’s production. He noted that his usual weight ranged between roughly 84 kg and 91 kg, but he maintained around 76 kg throughout the shoot. He added that he had not been that light since his teenage years.

The actor described the process as demanding, involving sustained training and careful dietary control. He later shared that he has continued to stay gluten free even after filming wrapped, joking that he has even found a gluten free beer he enjoys.

What gluten is and why some avoid it

Gluten is a protein found in wheat, rye and barley, and is common in foods such as bread, pasta and cereals. Some people must avoid it due to celiac disease, an autoimmune condition where gluten damages the lining of the small intestine. Others choose to avoid it because of gluten sensitivity or intolerance.

However, medical experts caution against assuming that gluten elimination alone leads to weight loss.

According to a Cleveland Clinic report, there is no scientific evidence that removing gluten by itself causes weight loss. The report states, “There’s absolutely no evidence that simply getting rid of gluten will result in weight loss.” It adds that people on gluten free diets may lose weight indirectly by making more conscious food choices and eating more whole foods such as fruits, vegetables, legumes and lean meats, which are often lower in calories.

A history of extreme transformations

This is not the first time Damon has undergone dramatic physical changes for a role. For the 1996 film Courage Under Fire, he lost approximately 18 to 23 kg in a short period, later admitting that the rapid weight loss led to serious health issues. He has said a doctor warned him that the process could have caused permanent heart damage.

By contrast, Damon has also spoken about how gaining weight was far easier. For The Informant! in 2009, he put on nearly 14 kg, describing the experience as enjoyable and effortless.