Few film-makers can say that their work has made a change to the real world, but Morgan Spurlock had a stronger claim than most. His 2004 documentary Super Size Me, an exposé of how the fast food industry was fuelling America’s obesity epidemic, appeared to have direct repercussions for the world’s largest fast food chain, McDonald’s.

Shortly before the film came out in May that year, the company introduced its Go Active! menu, which included salad items; six weeks after its release, the company abolished its supersize portions entirely.

McDonald’s claimed these menu changes were a coincidence. But the director, who has died aged 53 of complications from cancer, struck a timely blow at the business when awareness about fast food’s corrosive role in public health was on the rise.

Super Size Me’s high-concept premise – eating three McDonald’s meals for 30 days straight – was key to conveying Spurlock’s message. With the director gaining 11kg, plumping out his body fat from 11% to 18% and inflicting heart palpitations, impotence and depression on himself, his gonzo approach put him at the forefront of the early noughties boom in cinematic documentaries instigated by Michael Moore. “There’s real power in a documentary,” Spurlock later said.

Doubts later emerged about Spurlock’s experiment in bodily attrition, after he refused to release his diet logs from the period; and then when it later emerged that he was an alcoholic who had also imbibed during the shoot.

An inveterate attention-seeker and twinkly-eyed showman, he was not going to let these details affect either the purity of Super Size Me’s marketing line, or his emerging career as a documentary star; a budding Moore for the Jackass generation. He would consistently target totems of modern capitalism and consumerism, though none of his subsequent works had the same kind of influence as his 2004 lightning-bottler.

Spurlock was born in Parkersburg, West Virginia, and grew up in Beckley in the Methodist household of his auto-repair shop-owning father Ben and mother Phyllis, an English teacher and high-school counsellor. Though his parents later divorced, he credited his mother in particular with instilling in him a sense of activism: “She was one of those people who speak up when she didn’t agree with things. She was a collector of people too: if you had the ability to help people, you should,” he told the International Documentary Association.

A childhood fan of British humour such as Fawlty Towers and Monty Python, he was already exercising his entertainer’s streak doing “funny walks” around the house aged six or seven.

Rejected five times by University of Southern California’s film school, he graduated from the New York University Tisch School of the Arts in 1993. “I wanted to be Spielberg. I wanted to write and direct scripted movies,” Spurlock told Interview magazine. He originally showed promise in this direction, winning an award for his stage play The Phoenix at the New York international fringe festival in 1999.

After stints as a personal assistant on Woody Allen’s Bullets Over Broadway and Luc Besson’s Leon (both 1994), Spurlock first stepped in front of camera as a promotional spokesman for Sony Electronics. But his breakthrough came though hitching himself to the reality TV bandwagon with the self-created internet webcast, and, later (in 2002), MTV show, I Bet You Will. As one of the presenting team, Spurlock goaded members of the public into humiliating themselves for money – with stunts such as being “wedgied” or eating a worm burrito.

Super Size Me grossed $22m on a $65,000 budget, making it one of the most profitable documentaries of all time. Spurlock believed his body never fully recovered – though he lost the weight thanks to a special diet concocted by his then girlfriend, the vegan chef Alex Jamieson (the pair married and had a son, Laken, in 2006, before divorcing in 2011; Spurlock had been previously married to Priscilla Somer between 1996 and 2003).

He also later expressed doubts about the longer-term impact of Super Size Me on fast food corporations, later reflecting: “People say to me, ‘So has the food gotten healthier?’ And I say, ‘Well, the marketing sure has.’”

Spurlock could not skewer the zeitgeist again to create a second “doc-buster”, despite tilting at big-hitter topics such as terrorism (in 2008’s Where in the World is Osama Bin Laden?) and product-placement and advertising (POM Wonderful Presents: the Greatest Movie Ever Sold in 2011). With his trademark moustache, he settled into a reliably affable front-of-camera presence nosing around socio-cultural issues and foibles – sometimes fatuously.

In total, he directed and produced nearly 70 films and series, including a One Direction hagiography in 2013 and a Super Size Me sequel in 2017. But he retained keen business sense and marketing nous throughout this prolific output. “He taught us that we have to be chief executive artists,” his fellow documentary-maker Ondi Timoner told Variety.

Towards the end of Spurlock’s life, his career was on hold after he confessed in a 2017 blogpost to sexually abusive behaviour, including an allegation of rape while at college and paying off a production assistant he had harassed. “I have been unfaithful to every wife and girlfriend I have ever had,” he also wrote, explaining he had been sexually abused in his youth. He divulged all this possibly pre-emptively in anticipation of future accusations in the upswell of the #MeToo movement.

Making himself the focus of the story was true to his modus operandi, and his professed desire for self-improvement could indeed have made a fascinating documentary.

But the mea culpa proved an effective self-cancellation, with him resigning from the production company, Warrior Poets, he had founded in 2004 and being sued by Turner Entertainment Networks for an aborted project.

He divorced his third wife, the producer Sara Bernstein – with whom he had a second son – in 2024. His final documentary credit was for a mockumentary creating a fake history around the classic 1992 Simpsons episode Homer at the Bat.

Spurlock is survived by his children, Laken and Kallen, by his parents and his brothers, Craig and Barry.

• Morgan Spurlock, director and producer, born 7 November 1970; died 23 May 2024

• This article was amended on 29 May 2024. An earlier version described Spurlock’s moustache as “handlebar”. It has also been described as “horseshoe”. Spurlock himself used the term “handlebar” in a 2012 piece for the Guardian. For the avoidance of dispute the word “handlebar” has been removed.