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The Burger "Experiments"

by Steven Novella, Oct 18 2010

We have been getting a great deal of e-mail asking about the various “experiments” on YouTube (inspired by events on Fast Food Nation) in which a McDonald's hamburger and fries are left out for weeks or months. To the surprise of some, the food does not rot away to nothing but instead shrivels a little and becomes hard and shiny, but does not get moldy or rotten. The implication is that there is something wrong and unnatural about food that doesn't rot when left out.

Unfortunately this is what passes for “science” on the interwebs. But it does provide a teaching moment – with lessons about scientific methodology and how the logic of interpreting evidence.

The first thing I need to point out is that none of these “experiments” are actually experiments. They are simply observations. Observation is an important component of experiments, but the raw act of observing is not sufficient to establish an experiment. In fact, in medicine we divide clinical evidence into “observational” and “experimental.”

In order to conduct a scientific experiment you have to control for some variables. There has to be a comparison between different groups so that variables can be isolated. Setting out a hamburger and seeing what happens is an observation – but there is no controlling for variables, so it is not an experiment.

I don't think I am being pedantic. There is much that passes for science on television and the internet that is a gross distortion of science and teaches the public misinformation about what science actually is. Every ghost hunting show, for example, makes the same mistake as the hamburger videos – they make observations and then draw highly speculative, fanciful, and unwarranted conclusions from those observations. They think they are doing science because sometimes they are making those observations with fancy equipment. But I have never seen a ghost hunter actually do an experiment, and control for variables that might help determine what the nature of the phenomena they are observing is.

Let's consider what variables might be interesting to control for with the “rotting hamburger” question. The most obvious one would be to set out McDonald's hamburgers (more than one so that we can at least do some statistics) and compare them to a group of hamburgers that are home cooked with known ingredients vs hamburgers from another restaurant chain. But there are other variables also. How well are the hamburgers cooked (which relates to their moisture content at the beginning of the experiment)? There are many environmental conditions that should also be controlled for, if not varied to see their effect: humidity, temperature, ventilation, and light exposure.

An experiment looking at these variables for comparison would be an actual experiment and would tell us something – unlike the videos on YouTube.

This raises another point – the best experiments are designed to test specific hypotheses, and you should have some idea beforehand how the results will affect each hypothesis. For example, there are two primary hypotheses with the hamburger question: what determines the result of the left-out hamburger – is it primarily characteristics of the hamburger or characteristics of the environment, and which ones.

My hypothesis (we discussed this on the SGU this week, but to extend that discussion a bit) is that environmental factors, specifically temperature and humidity, are the most important. But also the beginning moisture of the hamburger and the thickness of the hamburger are likely important because these variables will determine how long it takes for the burger to dry out. Is that amount of time enough for mold to form? I note that McDonald's hamburgers are thin and thoroughly cooked, and will therefore dry out quickly (especially in a dry environment) – too quickly for mold to form. Thoroughly cooked meat should also be free of bacteria to cause rotting. So in the end you will have a dried hard patty, but it will no become moldy nor will it rot.

I do not think there is anything inherent to the ingredients of the hamburger that will significantly affect whether or not it molds or rots – which is the exact implication of these YouTube videos. In order to conclude that it is the hamburger ingredients that are to blame, experiments that control for thickness, degree of cooking, and environment need to be done so that the property of the burger itself is isolated as a variable. And then you will need to spend some time scratching your head to see if you can think of any other variables you forgot, while your colleagues specializing in the natural history of left-out hamburgers do the same, until we can be reasonably sure that every plausible variable was accounted for (I say plausible, because there are in unlimited number of implausible variables, like the phase of the moon when the burger was cooked).

If this question were taking seriously, it is probably true that a complex picture will emerge. Perhaps environment is the key factor, along with thickness and juiciness of the burger. But more subtle variables may emerge, such as the leanness of the beef, or the amount of salt added. Genuine controversies may emerge over conflicting or ambiguous evidence, making for some lively scientific meetings.

But in the end I believe the evidence will speak and a consensus of scientific opinion will emerge. Sure, there will be deniers – perhaps some genuine scientific dissenters, but also those with an anti-fast food ideological agenda, for example. They may even form a community of deniers, creating their own websites, and doing their own dubious experiments that science bloggers will then have to spend time criticizing and pointing out all the flaws. The political parties will likely come down on opposite sides of the question, each accusing the other of “junk science.” The news media will always cover the story as a genuine scientific controversy, long after a solid consensus has emerged, and will interview the same few cranks on the denier side for “balance”.

OK – maybe I got a little carried away with this analogy, but you get the idea.

45 Responses to “The Burger "Experiments"”

  1. Max says:

    America’s Test Kitchen should look into this. They try everything a hundred different ways.

    I never had a baguette get moldy. It quickly dries out and that’s it. No preservatives necessary.
    It’s the packaged breads in plastic bags that have preservatives like calcium propionate, sorbic acid, and potassium sorbate.

    I guess the Happy Meal turned into crackers, beef jerky, and potato chips :-)

  2. Bob Mcbride says:

    The observations made in the movie supersize me show burgers and fries in similiar environments with similiar fast food. And the fast food not rotting in similair conditions.

    • LovleAnjel says:

      The fast food did rot, except for the fries – it just took a longer time. I would speculate that the fries didn’t rot because McDonalds used a higher fry temp than the other restaurant, meaning the fries were effectively sterile when they were put in the sealed jar. Not any worse for you than Pasteur’s chicken broth.

      I would worry more about the food that rotted really quickly – higher bacterial counts and all.

  3. Bob – I know. It was still only a pseudo-experiment. They did not really control for sufficient variables, like moisture content. I also just don’t trust the content of Supersize me – the movie is known for making a number of scientific distortions.

    • Methos says:

      True enough – this movie has a point to make. However, at least in “Supersize Me”, they use a couple different kinds of burgers & fries (McDonalds, hope prepared, etc). So, I would have to say that the Supersize Me version does go past being an observation and qualify as an “experiment”, albeit a poorly constructed one.

    • Bob Mcbride says:

      Steve, thanks for the response. Do you find it compelling that the guy in Supersize me did control for environmental factors by keeping the fastfood and homemade food in the same area? I also wish that he had left his bias at the door.

  4. Max says:

    McDonalds will have to tell its employees to spit in the food so it spoils faster :-p

  5. Dennis says:

    In cae you haven’t seen it, J. Kenji Lopez-Alt over at Serious Eats has already begun conducting an experiment with McDonald’s burgers v. some home-prepped burgers. Information is in his post here:

    It’s not perfect, but it’s certainly a step in the right direction.

  6. GoneWithTheWind says:

    If you look at the picture you will notice the hamburger has no condiments and appears to have been dried before the experiment. No doubt there was some attempt to insure the air in the room remained dry. Like any phony pseudo-scientific experiment or “study” this was tainted from the beginning with an agenda. This is becoming the norm. Little valid information is disseminated from legitimate scientific work. Instead it is reduced to a headline or the underlying data is used in a data dredge to come with any anomoly that appears to support the agenda of the “researcher”. This is as much the fault of the legitimate scientists as it is those who misuse the science. The legitimate scientists usually remain mute when newspapers and special interest groups misuse their findings and data. I fully expect this problem to get worse.

  7. Trimegistus says:

    By the way: so what? How does the speed at which something rots affect its food value or flavor?

    • Max says:

      If the food doesn’t rot, this suggests that instead of it being served fresh, it’s full of preservatives and/or antibiotics. If that’s the case, and the preservatives are not listed among the ingredients, or the food is advertised as fresh, that would be fraud.

      • Trimegistus says:

        And why the hell would McDonalds’ bother to do that? They don’t make money by storing up burgers, they make money by moving them out the door or the driveup window.

        This makes about as much sense as the kangaroo meat legend.

      • Max says:

        Why add artificial color to chocolate cookies? Doesn’t make sense to me, yet I’ve seen it.
        I once asked for food without MSG in a Chinese restaurant, but they said they couldn’t do it because it was already in their ingredients. Maybe they save money that way, who knows.

      • DanTastic says:

        If you choose to try to avoid MSG, you may find it exceptionally difficult to do so. Not only does it occur naturally in many foods such as tomatoes, grapefruit, potatoes, apples, oranges, and mushrooms, but it is also added to an extremely wide variety of commercial products. With natural, unadulterated, unfermented foods, MSG-sensitive people do not react with symptoms to proteins that contain either bound or free glutamic acid. However, MSG-sensitive individuals do react to the glutamic acid of MSG in its free form, and, especially if it has been created through fermentation or some other artificial manufacturing process.

      • LovleAnjel says:

        The food is shipped to the stores frozen, so they don’t need preservatives for transport. Most of it is cooked from the frozen state, so it doesn’t need to keep on a shelf. They don’t want you to wait and eat their food when it’s cold, because it tastes even worse than normal. It doesn’t need to keep well in the consumer’s hands for more than about a half-hour. It makes no sense to spend money on adding lots of preservatives to food that is frozen right up until it’s cooked and eaten.

      • Max says:

        Well yeah, that’s why we expect restaurant food to be free of preservatives and thus perishable, so the fact that it didn’t rot was unexpected.

  8. Brian says:

    If the burger rotted much faster, then it would be touted as evidence to the same general conclusion: the burger is bad for you. Although it would be because the food is tainted in some fashion (feel free to make up the details since no *real* evidence is available).

    The main point that is seized upon is that the results are “different”. Different from what you think is best must mean it’s not as good.

    Like Trimegistus said, “so what”? One must still establish the link between rate of rotting to some legitimate measure of health. Of course by now, Joe Public has flipped the channel…

    *Disclaimer: I in no way am suggesting McD’s burgers are good for you. :)

  9. MadScientist says:

    Once upon a time I used to leave food out and I’d be surprised (and angry) if it *did* rot. I’ve used that technique to dry various types of fruit, fish, shrimp, pork, beef, and even chicken. Around the world there are still many people who dessicate food that way. It’s simply a matter of a little control of the environment to ensure that things don’t rot and do not become infested with maggots.

  10. BriansAWildDowner says:

    If McDonalds really had created some form of preservative that could make food last as long as these people claim…wouldn’t that be sorta big news?

  11. GoneWithTheWind says:

    More to the point of McDonalds food (and all fast food) were bad for you would we continue to set new records every year in longevity and decreases and disease? Exactly how many big Macs or fries does it take to kill me. Will one do it? A hundred? A thousand? And how many “organic” veggies does it take to counteract a happy meal? Will an apple a day really keep the doctor away? Will eating some fad movie star diet actually make me happier, healthier and more beautiful?
    My 24 year old son is 120 lbs, with his shirt off you would think he works out all the time, a six pack and what appears to be zero fat. And he eats junk food, McDonalds, Arby’s, about 2 gallons of soda a day etc. (I know someone is going to say he will die at 40 or be obese, whatever!) But my point is he eats 4000 calories or more everyday and eats almost only junkfood and he is skinny, active and healthy. I thought it was the junkfood that made children obese? In fact when I go to the McDonalds closest to the high school at lunch I see dozens of school kids eating there and none of them are obese or even overweight. How can that be???

    Obesity is genetic. You get it from your mom and dad not from McDonalds.

    • Max says:

      The same Libertarians who deny Anthropogenic Global Warming and smoking hazards also deny the obesity epidemic.

      “Although the Social Security Administration recently raised its estimates of how long Americans are going to live in the 21st century, current trends in obesity in the United States suggest that these estimates may not be accurate. From our analysis of the effect of obesity on longevity, we conclude that the steady rise in life expectancy during the past two centuries may soon come to an end.”

      Check out the diabetes trend, a 129% increase in 28 years.
      According to the American Diabetes Association, 11% of Americans over age 20, and 23% over age 60 have diabetes.
      Americans who are obese are nearly three times as likely as those who are not obese to report having been diagnosed with diabetes. More than one-fifth (21.2%) of obese adults are diabetics, compared to 7.4% of non-obese adults.

      So GoneWithTheWind, it’s your anecdote against the statistics. Next you’ll tell us about your grandma who lived to 100 while smoking three packs a day.

      • GoneWithTheWind says:

        First, let me dispel the diabetes myth. We have a dramatic increase in diagnosed diabetes because we had a dramatic increase in testing for diabetes. The number of people with diabetes didn’t go up we simply found the diabetes that people did not know about. But more importantly you do not get diabetes from your food. This is one of the worst disservices our media has done for us. by spreading this false belief. Diabetee is genetic you get it from yur parents not your food. IF you have diabetes then diet can indeed help you control it. But eating a diet intended for a diabetic will NOT prevent diabetes.
        As for obese people being three times as likely to report having diabetes I say DUH!! Diabetes has many symptoms and one of them is uncontrolled weight gain. The weight gain is a symptom of diabetes not the cause.

      • Max says:

        You know something that the Mayo Clinic doesn’t?

        “Risk factors for prediabetes and type 2 diabetes.
        It’s clear that certain factors increase the risk, however, including:
        Weight. The more fatty tissue you have, the more resistant your cells become to insulin.
        Inactivity. The less active you are, the greater your risk. Physical activity helps you control your weight, uses up glucose as energy and makes your cells more sensitive to insulin.”

        The list of symptoms includes unexplained weight loss, not uncontrolled weight gain.

      • GoneWithTheWind says:

        It is laughable. Apparently doctors take such a heavy load of medical classes they don’t have time to take any statistics classes. Correlation does not imply causation. I remember one of the more humorous blunders by a PhD candidate who studied why people in Florida apparently lived longer then people in other states. He listed some likely reasons based on correlations he discovered such as pure water and sunshine, etc. His dissertation was accepted and he got his degree and it was much later that someone pointed out that the reason there were so many older people in Florida is because they moved there for retirement NOT because the water made them live longer. If I get sick I want a doctor and the Mayo clinic would be my first choice. If I have a statistical problem I want a statistician not a doctor. The bottom line is obesity is a symptom of diabetes not a cause. There are numerous things you can do to alleviate the symptoms of diabetes (and you should) but there is NOTHING you can do to “cure” it. It is genetic.

      • Max says:

        Did you miss the part about diabetes causing weight loss rather than weight gain?

        Also, the claim that “Americans who are obese are nearly three times as likely as those who are not obese to report having been diagnosed with diabetes” says that diabetes is overrepresented among the obese, which is a stronger indication of obesity causing diabetes than if it just said that obesity is overrepresented among diabetics.

      • Max says:

        This just in

        “If current trends continue, as many as 1 in 3 U.S. adults could have diabetes by 2050, a report of the CDC says…
        However, via proper diet and physical activity the risk of diabetes can be reduced, the report says.”

      • GoneWithTheWind says:

        Just an example of the misinformation in your newspapers. It is a simple fact that a large portion of our population have diabetes and do not know it. Usually this diseases progresses as you age and the symptoms become more obvious. Indeed IF you are diabetic and do not know it then following a diabetic diet and excercise will put off most of the symptoms. To the ignorant this appears to mean that you can “prevent” diabetes by diet and excercise. For the 2/3rd of Americans who do not have diabetes no amount or lack of diet and excercise will give it to you. Diabetes is genetic much like the color of your eyes is. Would you consider dieting or excercising to change the color of your eyes?

    • LovleAnjel says:

      “I thought it was the junkfood that made children obese? In fact when I go to the McDonalds closest to the high school at lunch I see dozens of school kids eating there and none of them are obese or even overweight. How can that be???”

      You’re missing a piece of the equation: activity. Eating more calories than you burn causes weight gain. If your son was not “active and healthy”, but sat around on the couch doing nothing while eating 4000 Calories a day, he would be obese.

      The kids you see eating at McDonald’s may not be obese because A) they get in a good amount of activity & growth that uses up all those Calories, and/or B) they are not overeating McDonald’s. My niece & nephew eat fast food every time their Dad has them, but they only take a few bites and then stop. Skinny as willow switches.

      • GoneWithTheWind says:

        So you are agreeing then that it isn’t the jubkfood or the sugary drinks that cause obesity???
        Obesity is largely genetic. If your mother or father was obese you will probably be obese as well. If you are gentically predisposed to be obese it is almost impossible to achieve a “normal” weight and would require a lifetime of starvation dieting.
        To simply say that the reason some people aren’t obese is because they are more physically active begs the question. They are more physically active because that too is a genetic trait. Does it matter that you are genetically predisposed to eat too much or do too little? Either way you consume more calories then you use.

    • GWTW:
      1. “We” don’t set new records every year. Countries like Japan do, even as the U.S.’s ranking in average lifespan continues to slip.

      2. Obesity is more complex than you try to present it.

      3. @Max – his grandma was smoking the 3 packs a day while riding a Hog and eating Big Macs and using a cell phone, all at the same time.

      4. BUT … that’s because smoking also has just a statistical, not causal, correlation.

      5. GWTW, you apparently are so biased, ignorant or both that you don’t even know the difference between Type I and Type II diabetes. #libertarianismpennandtellerfail

      6. And, it’s pseudoskepticism like this, libertarianism in disguise (I love the “your newspapers” – I guess Murdoch hasn’t made the WSJ Faux enough yet) that’s off-putting to some people about legitimate skepticism. #pseudoskepticismpublicrelationsfail

      • GoneWithTheWind says:

        You are in denial. Every year our life expectancy goes up. This is called setting new records. As for Japan you would be comparing apples and oranges. Japan is 99.999% ethnic Japanese. The U.S. is about 65% ethnic European and a melting pot of other ethnic groups. Many of these other groups have genetic diseases which reduce their life expectancy.
        Obesity is largely genetic. What could be simpler then that???
        I assume 3 & 4 were feeble attempts at an insult.
        How could anyone not know the difference between type I and type II diabetes? What have I said that gave you that impression? Or was that another feeble attemtp at an insult?
        #6 seems inane was there a point in ther somewhere?

  12. Marcel says:

    Always question the person making the claim’s intention. That’ll take you halfway to the truth.

    Nevermind what we eat or consume, due to the richness of our lives in modern times, most of us eat and drink that which is bad for us in large quantities, and I’m not talking junk food either (your favourite French restaurant will probably kill you in weeks or months with some of their dishes if you “live” on it like in Supersize Me).

    Common sense. If only it were common.

    • GoneWithTheWind says:

      Common sense!! Do you really believe McDonalds is poison or that there are actually magic “good” foods?? IF you have a disease that requires you to follow a particular diet then by all means follow that diet. Otherwise all you need to do is eat a wide diversity of food and do not self-limit your diet or follow fad diets. There are no magic foods and there are no bad foods. The only mistake is eating too much of one thing or one type of food or getting too little diversity.

      By the way, Supersize Me was a mockumentary intended put push a biased point of view. I watched it and thought he could not be serious but was amazed at the incredible number of people who ate up (pun intended) pap he feed them. So I repeat my challenge: How many happy meals does it take to kill me? Surely one of you food bigots has some idea? I’m 67, love McDonalds, not dead yet. Maybe it’s not possible! Maybe (this is scary) food is just food and your digestive system simply breaks it all down into it’s components and uses it to either power your body or rebuild your body and has no clue where it comes from. Maybe the protein from a McDonalds hamburger is just as good as the protein from _____ (fill in the blank from your good food list) and your body doesn’t care. DUH!

      • tmac57 says:

        I agree in part with your view that there isn’t a good reason for singling out McDonald’s as a “bad food”, but as you stated,”The only mistake is eating too much of one thing or one type of food or getting too little diversity…”
        I assume that you would agree that a diet ONLY consisting of burgers,fries and soda would probably be a poor choice.That is what the ‘Supersize Me’ movie was getting at in a ham handed way. The liberties he took with his ‘experiment’ probably didn’t help the message in the long run,but the bigger picture of needing more diversity in the modern diet is not entirely wrong headed in my opinion.

      • GoneWithTheWind says:

        I think you are actually agreeing with me. My view is that we should eat a diverse diet and avoid fad or exclusionary diets. But if you have health problems that require a specific diet then by all means follow that advice. One of the problems in this discussion is people assume that since a particular diet is “good” for you if you have a particular disease then it must also prevent that disease. Superstition is rampant in food beliefs and almost all of the “old wives tales” turn out to be false.

        The supersize Mocumentary was a hit piece nothing more nothing less. It wasn’t an experiment. It was not intended to discover anything or find any truth. It was an effort by a biased person to push his biase on everyone else. As such it was contrary to science and worse then useless.

      • Max says:

        “Maybe the protein from a McDonalds hamburger is just as good as the protein from _____”

        Hmm, why did you mention the protein and not the fat and the carbs? Is it because you know that the saturated fat and the empty carbs in a McDonalds hamburger are worse than the unsaturated fat and complex carbs in other foods?

      • GoneWithTheWind says:

        Max, Do you consume any fats and oils? Your body requires them. In fact you will die without them. Unless you are a vegetarian I assume you eat meat. A McDonalds burger is just meat. Most people who dislike McDonalds but are unable to explain why eat hamburger at home. They generally have no clue as to why exactly because the burger is served at McDonalds it is somehow “poison” while the hamburger they eat at home is nutricious.

        The entire saturated/unsaturated fats discussion is steeped in mysticism and superstition. When I was young we were told to not eat butter because the fats were bad for you but instead to eat margarine and that it was better for you. Years later they decided that indeed margarine is worse then butter. I think today the great minds and scientists who have been wrong on everything decided neither one is good for you. But the fact remains that here in the U.S. all adults were brought up eating margarine, butter, hamburger, pork, etc. and we once again this year broke records on longevity. Why is that? Is saturated fat bad for everyone or only bad for people with a genetic predisposition to have high cholesterol. Did these ever-failing pseudo-scientists once again conflate the fact that with some diseases certain food are bad for you with the concept that those same foods are bad for everyone?

        Empty carbs!!! You are kidding, right? Do you EVER eat bread at home? Why would you eat those “empty carbs”? What is a full carb? Presumably you mean apples or sweet potatoes (both very good foods). But what if you are already getting 100% of your MDA of vitamins and minerals and you need calories? Hmmmmm! I suppose even then you want “full carbs”. Give me a break! In the Western world our diets are so full of vitamins and minerals that only those people who follow a self-limiting diet need more vitamins and minerals. And I hope you are aware that some vitamins and mineral in excess are harmful/toxic.

      • Max says:

        I’m still curious why you mentioned protein and not fat and carbs. Would you go further and say that the protein, fat, and carbs from a McDonalds hamburger are just as good as the protein, fat, and carbs from, say, salmon and couscous?

      • I think Marcel in part was commenting about YOU, not just Supersize Me, as far as “intent.”

  13. GoneWithTheWind says:

    Two points: I remain unconvinced that the entire fat arguement (i.e that some fats are magic while others will kill you) has been proven or even has enough evidence to warrant changing habits just to be on the safe side. There are people who are born with a gentic predisposition to create too much cholesterol in their blood. They have a serious health problem that can only be helped by diet and some serious medication. Often they are advised to completely avoid saturated fats and cholesterol in their diet and since fats are essential for life they are advised to use unsaturated fats. Does that advice translate to every person on earth? Will saturated fats kill you? If you believe that then you have a steep burden of proof. There are literally billions of people on earth eating saturated fats who live as long as those people who substitute unsaturated fats. So is salmon better for you then a hamburger? How many hamburgers does it take to kill me and how much longer will I live for each salmon meal I consume? That is your challenge! That is the question you cannot answer. Until you can answer that then you have no business implyng that a McDonalds hamburger is “bad” for you while salmon is “good”.
    Make no mistake I am aware of the many books, websites, doctors and pundits who are preaching this particular “good food, bad food” religion. What I am saying is they are either simply ignorant or they are scamming you. There is no “magic” food. And there are no bad foods. Eat a varied diet and avoid fad diets or restrictive diets and you will be eating healthy. If you have a disease that requires a specific diet then by all means follow your doctors advice.

  14. Mark Vaughan says:

    Great article. Although only one experiment (not yet repeated, but thoroughly documented should one want to repeat it), you can see what happens when a control burger (organic home made beef burger made to the same specifications as a fast food burger) is placed in a humid environment with a McDonalds Burger, Burger King Burger and an organic tomato here:
    Another experiment is underway to test the drying out theory, it can be found here:

  15. Newsflash, folks: McD’s rots. Including the fries.

    I set up an experiment controlling for the following variables:

    moisture (3 levels)
    2 types of fats (McD’s veggie oil blend vs. beef tallow in homemade fries)
    salt content
    homemade burgers and fries vs. McD’s.

    You can see the results in video right here:

    Heaven forbid the media catch onto reality.

  16. Max says:

    The Big Mac buns contain preservatives calcium propionate and sodium propionate, same as packaged bread, so fast food does use preservatives.