Written and medically reviewed by Katya Meyers, RD
If health science headlines are to be trusted (breaking news — they aren’t), breakfast is either the most important meal of the day . . . or the least. Running can be good for weight loss . . . but can also cause inflammation-driven weight gain. And ice baths are either the untapped fountain of youth . . . or a total waste of time. With contradictions like these, which side is right? Both? Neither?
It can be difficult to untangle what is true from what is not when it comes to health news. Fortunately, there are strategies you can employ to help you increase your scientific literacy and, ultimately, decide whether you want to take the advice to heart or not.
Why Increasing Your Scientific Literacy Is Important
When we say “scientific literacy,” we’re essentially referring to your ability to read and evaluate the legitimacy of a health claim. It’s an important skill to cultivate because, with the advent of the internet, the number of health claims are skyrocketing. Sure, snake oil was being peddled as a cure-all in the 1800s and checkout-aisle tabloids were promoting grapefruit diets as recently as the 1990s. Today, however, a person might be pelted with hundreds of claims every day, all thanks to the internet-fueled explosion of the information economy.
From Instagram Reels, to retweets from friends, to pop-up ads, to magazine articles, the internet is a free-for-all. There are no referees, which means you’re in charge of discerning fact from fiction. And while common sense can weed out some of the noise (“if it’s too good to be true, it probably is”), there are a lot of claims that require a greater degree of scientific literacy to untangle.
Is the Source Credible?
Deciding whether or not a health claim has merit begins with thinking critically about whether the source of the claim is credible.
#1. Identify the Source
The best source, of course, is the original one — namely, the scientific study on which the claim is based. However, let’s face it: scientific journals don’t exactly make light reading. That’s why there are so many publications and companies out there doing the interpretation work (ourselves included!). The vast majority of the health claims you find online are likely to be some sort of interpretation, rather than original research, so the key is to identify whether the interpretation is trustworthy. The way to do this is by identifying the interpreter, i.e., author.
#2. Check Credentials
If there is an author connected to the health claim (and you can interpret “author” loosely; podcast guests, social media personalities, and bloggers all count), check their credentials. What is their educational background, and do they have practical experience in the field they’re discussing? Have they written or spoken on related topics? Although it certainly does not guarantee accuracy, advanced degrees in a health-related field (e.g., MDs, RDs, PhDs) and/or extensive research or clinical experience can be an indication that the individual has the training they need to critically evaluate the advice they’re giving.
#3. Look at the Links
Sometimes, even people with expert-level credentials put aside their training in order to spread marketing claims that are invalid. (This occurs to the extent that the Federal Trade Commission has published a guide specifically about how to spot false weight-loss claims!) Therefore, a good litmus test is to check whether the source of the health claim links to a scientific study, ideally published in the last 5 years or so, to back up their claim. The main exception to this is if you’re reading or watching an interview with an expert; in that case, you’ll want to verify that they are currently researching and/or working with patients experiencing the phenomenon they’re discussing.
How to Evaluate a Published Scientific Study
Now that you’ve found the source credible and discovered the link to the study, it’s time to click that link. Many people shy away from taking this next step because they believe they’re not qualified to read complex science. Even if high school biology class seems like a distant memory, that’s okay! You can still evaluate a study using these simple questions.
#1. Does the Headline Match the Study’s Conclusion?
The quickest way to verify or debunk a health claim is to compare its headline or main takeaway with the study’s conclusion. You don’t have to go far to do this — just look for the abstract at the top of the study and read the last few sentences. (Sometimes, these sentences are even conveniently labeled “Conclusion.”) Do the two match? If so, that’s a great sign, and you can move on to further evaluate the study. If not, the person or company sharing the claim might be stretching or even flat-out misinterpreting the study’s findings.
#2. Is It a Human Study?
The best research subjects for learning about humans are humans. However, for logistical, ethical, and financial reasons, this is not always possible; therefore, scientists often rely on animal models for research. Some findings in animal studies can be applied to humans, but certainly not all — that’s why when a drug is being developed, it is first tested on animals and then undergoes an entirely new testing phase with humans before it’s considered for approval by the FDA.
Ultimately, differing physiology, genetics, and lifespan can make it difficult to translate the results of animal studies to humans, so be wary of overgeneralizing any studies on mice, chimpanzees, or fruit flies to your own health.
#3. How Big Is the Sample Size?
In a scientific study, the smaller the “n” or sample size, the more careful researchers (and journalists!) must be in broadly applying whatever was learned. Studies can range from individual case studies of just a few individuals to population-based meta analyses (a “study of studies”) incorporating data from thousands or even millions of individuals. Case studies with tiny sample sizes can be very interesting to read, but when deciding whether or not to hang your hat on the takeaways of a study, a larger sample size is usually better.
#4. What Was the Study Duration?
Changes from many health behaviors such as nutrition, exercise, sleep, and restoration can take many weeks or even months to manifest and require a certain level of stimulus. For example, resistance training is good for building strength, but studying the effect of one bicep curl per day for a week may lead you to believe that lifting weights has no effect. Likewise, an all-grapefruit diet may lead to weight loss after two weeks, but what are the subjects’ health metrics after two months? (Chances are they’re not following the diet anymore!) If the duration is too short, results can be inconsistent or unreliable, so consider the timeframe over which the study took place when interpreting results.
#5. Was the Study Peer Reviewed?
If the answers to the first four questions look promising, the last thing to check is whether the study was peer reviewed. “Peer review” is similar (though on a grander, more rigorous scale) to what you may have experienced in high school when your teacher asked you to prepare a presentation and your class gave you a critique. Before an article is accepted into any respected scientific journal, it goes through a rigorous vetting process, in which it is reviewed by fellow researchers in that field for accuracy and merit. Think of it as quality control for scientific literature.
To determine whether an article has been peer reviewed, start by searching for it in PubMed, an online database of (mostly) peer-reviewed scientific articles. If the article is not there, or to be doubly sure of its peer-review status, go to the “about” page of the journal where it was published. Peer-reviewed journals are proud of their academic rigor and will typically advertise this either on their “about” page or on their “submission guidelines” page.
Final Caveats and Considerations
Whether you’re reading the TL;DR (internet speak for “too long; didn’t read”) on social media, a journalist’s interpretation, or the original study itself, always keep in mind: Correlation does not equal causation. In other words, just because two variables are related (i.e., correlated), it does not mean one causes the other. This is one of the most common flaws in interpreting scientific findings and has led to a barrage of health misinformation. Correlations can be due to one variable causing the other, but they can also be due to random coincidence, a hidden variable, or a “confounding factor.” For example, shark attacks and ice cream consumption are highly correlated, but they are not causal—eating more ice cream does not cause more shark attacks! (The hidden variable is summertime.) Similarly, health research is often observational, and the initial findings can suggest that one thing (a type of exercise, a diet, etc.) can cause something it doesn’t.
Take a cross-sectional study showing a correlation between yoga studio members and healthy BMI, for example. Does this prove that yoga is great for maintaining a healthy weight, or is the relationship complicated by a host of socioeconomic factors? One might argue that those who can afford a yoga membership can also afford better-quality food and healthcare or have more leisure time to spend developing friendships and social support. Taking the time to ask “what else may be contributing to these findings?” is important when evaluating a health claim, no matter where you find it.
Finally, even if a study passes all of these tests, no study is perfect, and even well-designed studies can draw flawed conclusions. Therefore, never use a single study as the sole reason you revamp your health routine. Instead, consider what other research exists and how the current study or article you’re reading fits into the larger context. If multiple large-scale studies show similar results, that’s an indication that you’re on the right track, and a revamped health routine might be in order.
Conclusion
It’s not always easy to discern what’s reliable when it comes to advice in the health sphere. But, when armed with some knowledge of the subject, healthy skepticism of advice that is “too good to be true,” and a willingness to seek out trustworthy sources, you’re likely to chart a fairly good course through the wild West of science news.
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