Modern Diet Myth No. 1: Eating McDonald’s makes you fat and sick

For years, the food served at McDonald’s restaurants has been used as an example of all that is wrong in modern western diets – it’s simple, fast, cheap and American, and therefore couldn’t possibly be good for us. In his 2004 movie Super Size Me United States film maker Morgan Spurlock set out to demonstrate that McDonald’s food actually makes people fat and sick, using himself as a guinea pig.

The Spurlock ‘experiment’

For 30 days Spurlock ate only McDonald’s food and documented the effects on his physical and psychological well-being on film. The effects were dramatic: he gained over 11 kilos in weight; his blood cholesterol went up; fat built up in his liver; and he experienced sexual dysfunction and swings in mood. At last, here was all the proof we needed that eating McDonald’s food makes you fat and sick!

In reality it was nothing of the sort. Proof comes from scientific experiments and Super Size Me bore no resemblance to science. When conducting dietary experiments researchers are careful to control for all the factors that might affect the result. If two things change in a diet, how do you know if an adverse effect is due to one thing or the other?

Spurlock gave his audience the impression that he was testing the QUALITY of McDonald’s food. However, during his 30-day ‘experiment’ he also changed the QUANTITY of food that he ate. In fact, he absolutely stuffed himself, doubling his calorie intake. This binge was why he put on so many kilos and probably why his blood cholesterol and liver fat increased.

The fact that he was eating McDonald’s food actually had nothing to do with his weight gain. Many dietary experiments have shown that diets with widely differing composition have exactly the same effect on body weight if calories are kept constant, and physical activity remains the same. These are the things that determine whether body weight moves up or down. Spurlock actually lowered his level of physical activity during his month-long feast, presumably to ensure the results were as bad as possible.

Image: source

Spurlock’s motive

What was Spurlock’s motive? If the intention had been to inform the general public of the facts Spurlock would have teamed up with some nutrition researchers and filmed a real scientific study into the effects of McDonald’s food. I suspect he was aware that the results would hardly have been big news.

At best, Spurlock’s movie may be an extreme case of white hat bias i.e. bias leading to the distortion of information in the service of what may be perceived to be righteous ends. But the predetermined outcome and the misrepresentation of its cause surely pushes ethics to the limit.

Alternatively, maybe Super Size Me was just a stunt designed to generate a lot of publicity and to tarnish McDonald’s name. Irrespective of what we think about the nutritional quality of McDonald’s food, wouldn’t we all be better off if we just heard the facts?

Declaration: Bill Shrapnel has no association with McDonald’s.


6 thoughts on “Modern Diet Myth No. 1: Eating McDonald’s makes you fat and sick

  1. True, Spurlock’s movie does not get a pass for scientific methodology. However he does demonstrate the typical amount of calories that so many Americans eat at fast food restaurants on a regular basis, especially since the Value Meal sizes are priced in a way that consumers “get more for their money” when purchasing the larger amounts.

    Larger Value Meals => More calories => Weight gain and associated mortality/morbidity

    • If only those who were concerned about addressing the obesity epidemic had focussed on calories from the start we may have made more progress in dealing with this problem. Instead, for 20 years the general public was told to eat less fat; in the case of Mr Spurlock’s film, the message was eat less Maccas; now they are being told to eat less sugar. It has all been about food composition and not about calories.
      And we wonder why people are confused. Regards, Bill

  2. I haven’t seen the film in a while but I was under the impression that he was demonstrating what happens when someone eats takeaway food for each meal. The fact that he used McDonalds, I thought, was because it is an international icon for fast food, just like Coca Cola tends to be the icon for soft drink. And the quantity went up because he attempted to demonstrate how McDonalds insist on adding more for little cost. He only accepted an upsize when offered, which was a lot of the time. He may have called it an experiment but I don’t think he ever intended to be all that scientific about it. It was entertainment for the masses, and his approach was appealing to people who aren’t particularly inclined to watch scientific programs. The film has been criticised many times for that.
    I think the message though, regardless of whether it is the means to a favourable end, is important. A slightly different example, but remote clinic staff once asked incredulously why even after bombarding people with the ‘Coke is bad’ message, which they seemed to take on board, people still attended clinic with a bottle of Fanta in hand. In fact, the people are listening to messages. The message was that Coke is bad, but the info that most other soft drinks had about the same amount of sugar wasn’t offered. They took the message very literally.

    • Hi Jenna
      I now spend a lot of my time in country NSW and whenever I eat out I am usually offered about 50% more calories than I could ever possibly eat, all at a reasonable price. This is not just a McDonald’s phenomenon; it’s the new normal. And this is what people need to learn to manage if we are ever going to get on top of the obesity problem.
      In obesity prevention there has been a lot of focus on changing environments. However, with the notable exception of schools, I think this focus is misdirected. The underlying environment is that food is abundant, tasty and cheap – and it’s not going to change much unless there is a war or a deep economic recession. How individuals and families interact with that environment is the key. When people follow their instincts they put on weight, but how do you overrule instinct?
      Regards, Bill

  3. Hmmmm…. it’s been a while since I’ve seen this film but I seem to recall it being as much, if not more, about quantity than quality. My impression was that it was largely a protest against the upsizing of meals at a minimal cost, a marketing ploy that encouraged people to consume far greater quantities than they needed. Hence, the very appropriate title “Super Size Me”. For the 30 day duration of his experiment Spurlock purchased and ate a super sized meal every time it was offered. The results being, that since it was offered quite often he therefore ate much more than he would normally. I thought the film achieved all that it had set out to do (plus a bit more… the film is believed to have been instrumental in McDonalds phasing out supersized meal deals within months of its release).

  4. I am going to do my own research on McDonald’s. I am going to eat the food that Morgan ate but adjust the quantities so that I only have 40% of the calories of his meals. Incidentally my total calories will be less than what I normally eat. I hope I don’t lose weight and that my bio markers don’t improve. Then it would clearly establish Maccas as a health food. I love rigorous scientific inquiry!!

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