(Well, it might, but you have no way of knowing.)

Since I have asthma, I tend to read news stories about scientific studies dealing with asthma. Today I saw this headline: “High-Fat Meal May Trigger Asthma.”

Since I do eat high-fat meals on occasion, I immediately read the news story. Based on the story, there is an obvious flaw in the scientific study. Let’s see if you can spot the flaw.

The study compared the lung inflammation in test subjects before and after a meal. The subjects were given either a low-fat meal or a high-fat meal. The low-fat meal was 13% fat. The high-fat meal was 50% fat. The low-fat meal was 200 calories. The high-fat meal was 1000 calories. Those who ate the high-fat meal had an increase in lung inflammation.

So, did you spot the flaw in the study?

That’s right: the high-fat meal had 5 times the calories of the low-fat meal.

How do the researchers know that it was the high fat content, rather than the high calorie count, that caused the increase in lung inflammation?  Answer: they don’t.  This experiment provides just as much support for the headline “High-Calorie Meal May Trigger Asthma.”

A properly designed experiment would have had the same calorie count for both the low-fat and high-fat meals, in order to eliminate calorie count as a variable.

Additionally, all the high-fat meals consisted of a hamburger and hash browns, and all the low-fat meals consisted of yogurt.  So there’s the possibility that beef or potato or some other particular ingredient of the high-fat meals causes inflammation, not the fat itself, and that a high-fat meal of bacon and eggs would not have caused inflammation. Or possibly yogurt has some property that suppresses inflammation, while a low-fat meal of pasta with tomato sauce would have caused inflammation.  The proper thing to do would have been to use at least two different high-fat and low-fat meals in order to reduce the possibility that something other than fat content was making the difference.

Note that I’m not saying that high fat content doesn’t cause lung inflammation. I’m just saying that this study is poorly designed and is therefore insufficient evidence for that conclusion.