What happened during Super Size Me?

December 25, 2025 •

3 min read

In the 2004 documentary Super Size Me, filmmaker Morgan Spurlock consumed nothing but McDonald's food for 30 days, triggering a massive public health conversation. What happened during Super Size Me shocked audiences, as he documented significant physical and psychological harm.

Quick Summary

Filmmaker Morgan Spurlock's 30-day McDonald's diet experiment in Super Size Me resulted in alarming weight gain, mood swings, and liver damage, bringing public attention to the health risks of fast food.

Key Points

Significant Weight Gain: Over 30 days, filmmaker Morgan Spurlock gained 24.5 pounds by eating exclusively at McDonald's.
Alarming Health Decline: Medical professionals were shocked by his rapidly deteriorating health, including liver dysfunction, a spike in cholesterol, and mood swings.
Undisclosed Alcohol Abuse: Spurlock later admitted to a history of heavy drinking, which could have been a factor in the severe liver damage documented in the film.
Triggered Corporate Change: Following the documentary, McDonald's phased out its "Super Size" option and began promoting healthier menu items.
Scientific Method Flaws: Critics noted the experiment was not a scientifically controlled study due to the lack of a control group and Spurlock's unreleased food logs.
Long-lasting Personal Effects: Spurlock reported that his metabolism was permanently affected, making weight gain easier even years after the experiment concluded.

The Rules of the 30-Day Experiment

To create the documentary Super Size Me, Morgan Spurlock adhered to strict guidelines for 30 days in 2003, aiming to illustrate the effects of a diet exclusively from one fast-food chain. His rules included eating three McDonald's meals daily, consuming every menu item at least once, only drinking bottled water besides McDonald's beverages, always accepting the "Super Size" option when offered, and maintaining low physical activity similar to an average American's 5,000 daily steps.

The Physical and Psychological Fallout

Spurlock, healthy at the start, was monitored by doctors. Despite mild initial predictions, his health deteriorated severely.

Documented Health Impacts

Within a month, Spurlock gained 24.5 pounds, increasing his body mass by 13%. It took him over a year to lose the weight. His liver function declined significantly, with one doctor comparing it to an alcoholic's liver. Cholesterol levels rose to 230, and his blood pressure increased. He also developed fat accumulation in his liver.

Psychological Effects

Spurlock experienced mood swings, depression, and lethargy. Doctors observed addiction-like symptoms: a brief high after eating, followed by a crash. His girlfriend noted a loss of energy and sex drive.

The Legacy and Controversy of the Documentary

Super Size Me significantly impacted public opinion and the fast-food industry but faced criticism regarding its methodology and Spurlock's later disclosures.

Scientific Scrutiny and Other Rebuttals

Critics argued the experiment lacked scientific rigor due to no control group and unreleased food logs. Counter-experiments showed high-calorie diets were harmful but didn't always replicate Spurlock's severe liver issues.

Spurlock's Alcohol Abuse Admission

Spurlock's 2017 admission of alcohol abuse, unknown during filming, led critics to suggest it contributed to his liver damage.

McDonald's Reaction

Six weeks after the film's premiere, McDonald's removed the "Super Size" option and promoted healthier choices.

A Comparison of Spurlock's Experiment and Rebuttals


Aspect	Morgan Spurlock's Experiment	Counter-Experiments (e.g., Fat Head and New Scientist)
Diet Rules	3 McDonald's meals daily, eat entire menu at least once, always "Super Size" when offered.	Calorie-controlled fast food diet; sometimes allowed other fast food chains.
Caloric Intake	Estimated 5,000 kcal per day, well above standard recommendations.	Varied, but often more mindful of portion size, leading to lower calorie intake.
Exercise	Reduced to match average American levels (~5,000 steps).	Controlled physical activity, sometimes with moderate resistance training.
Liver Damage	Significant, shocking decline in liver function observed by doctors.	Some participants saw elevated liver enzymes, but none experienced the extreme decline seen in Spurlock.
Weight Change	Gained 24.5 pounds in 30 days.	Some participants gained weight, while others on a calorie-controlled regimen lost weight.
Controversy	Lack of scientific controls and transparency (undisclosed alcohol abuse) questioned the validity of results.	Criticized for attempting to refute a sensationalist documentary, but provided more scientific rigor.

The Aftermath and Lasting Impact

The documentary's impact was significant, influencing the fast-food industry and public awareness of obesity. Spurlock faced personal consequences including long-term health effects, industry shifts like the removal of "Super Size" and increased demand for food labeling, and a complicated legacy due to later admissions and critiques.

Conclusion

What happened during Super Size Me was a powerful experiment that affected the discourse on fast food and public health. Despite its controversial, unscientific nature and Spurlock's later revelations, the documentary demonstrated the potential harms of a diet high in calories and low in nutrients. It highlighted the human cost of the obesity epidemic and prompted reevaluation of dietary choices. The film's legacy serves as a reminder of diet's impact on health. For more on the film's production and legacy, read {Link: grunge.com https://www.grunge.com/1589387/tragedy-super-size-me-director-morgan-spurlock-explained/}.

Frequently Asked Questions

The main rules were eating three McDonald's meals daily for 30 days, consuming every menu item at least once, only ingesting McDonald's products (including bottled water), accepting the "Super Size" option when offered, and minimizing exercise.

Over the 30-day period, Morgan Spurlock gained 24.5 pounds (11.1 kg). It took him over a year to lose the weight he gained during the experiment.

Spurlock experienced numerous health issues, including significant weight gain, liver damage, dangerously high cholesterol, mood swings, depression, lethargy, and a decreased sex drive.

Six weeks after the documentary premiered, McDonald's eliminated the "Super Size" option and began introducing healthier choices. While the company denied the film influenced its decisions, the timing suggested otherwise for many.

No, the experiment was not considered scientifically sound. It lacked a control group and peer-reviewed data, and Spurlock's later admission of undisclosed alcohol abuse further compromised the validity of the results.

Yes, several people attempted replications. Some, like the Swedish study referenced by New Scientist, yielded different results, finding that while a high-calorie diet is harmful, it did not always lead to the same severe liver damage Spurlock experienced.

Spurlock produced other documentaries and continued his career, though the Super Size Me experiment had a lasting effect on his body. He died in May 2024 from complications related to cancer, though his long-time doctor stated the fast-food diet was not the cause of his cancer.

After the experiment, Spurlock recovered his health with the help of a detox diet prepared by his then-girlfriend and a vegetarian cook, Alexandra Jamieson.