Be Science Savvy to Avoid Falling for Health Trends and Fad Diets

woman with skeptical expression

Have you tried every new fad diet and quick-fix health trend, only to find results and long-term benefits lacking? The latest fads can be enticing but often sound too good to be true. And they usually are. Learn how to sort through the pseudoscience and fake news to identify credible solutions for lasting change.

Moe was trying to lose weight and was willing to try just about anything. He consulted his friends who told him about a new craze: the witch diet. Apparently, if he added a brew of bat’s wing, eye of newt and frog legs to his meal plan he was guaranteed to shed the pounds.

Why do we fall for fads?

The diet sounded ridiculous, but a few things piqued Moe’s interest:


Moe loved the path of least resistance — we all do.1 This impulse is a holdover from eons ago when every spare calorie mattered for survival. The simplicity of a witch brew to melt the pounds away sounded so easy and offered such big results, that Moe just had to hear more.


Moe was bored with the same old diet plan and workout routine. His brain identified the witch diet as something new, and it subconsciously compelled him to seek out the unknown rewards.2 After all, not investigating might result in a missed opportunity.


Fear of missing out (FOMO) was built into Moe’s psyche. No one wants to be left out, especially when you can see what everyone else is up to online.3 Getting booted from the tribe for lack of participation used to be a death sentence, after all, so Moe was compelled to join his friends and not be the odd one out.

Moe still wasn’t sure — something about the diet set off his spidey senses. So next he “researched” what the interwebs had to say. He couldn’t deny all the pictures he saw online: attractive, lean, muscular people with the brew in hand. The diet must be working for everyone, right?

Probably not. It would have helped if Moe had known about a few things to consider when evaluating new information.

Shaky Science Pitfalls

Confirmation Bias

Even when Moe came across claims that the new diet didn’t work, he quickly passed over them and skipped to the next post. That comes as no surprise — research shows that our brains are biased toward evidence that supports what we want to believe. For example, one study showed that when two different speeches on a topic were available, listeners overwhelmingly chose the one that supported the view they already held. Why challenge your beliefs when you could sit back and be validated?4

Law of Truly Large Numbers

Of course there were success stories to be found; huge sample sizes almost guarantee that every possible outcome will happen.5 If Moe threw a million pennies into the air, some of them would almost certainly land on their edges, but that doesn’t mean they would *usually* land that way. Likewise, way more people will shout about their successes than admit to failure. So his feed was loaded with tales of dieting triumph even though, statistically, there were way more fails that no one was boasting about.

Placebo Effect

The brew got all the weight loss credit, but the real star could have been the placebo effect.6 That’s when someone experiences a result through suggestion alone, like when a headache goes away after you take something (even if you grabbed a breath mint instead of a pain reliever). You expect the headache to go away, and so it does. In the case of the witch diet, perhaps many people were less hungry and lost weight because they’d been told the brew was supposed to curb their appetites.

Correlation vs Causation

Moe didn’t consider that while some people on the diet were losing weight, it wasn’t because of the potion. Instead, they’d been chasing down frogs and bats to mix their own brew and were getting way more exercise in the process. In other cases, the brew might have been part of a larger diet and exercise lifestyle change. It wasn’t really the brew that made the difference. It was all the other things. So, weight loss and the witch brew were correlated, which means they were related, but one wasn’t actually causing the other.7


Lastly, Moe didn’t know that French dining was on the decline and frog leg distributors were looking to unload their overstock. They’d concocted the witch brew scheme and added outrageous claims to the mix to make a few more sales. And as sales soared, the claims got all the more outrageous. Marketing often plays a huge role in the hype around a new trend, but all those advertising dollars don’t necessarily translate to the promised results.8

In the end, Moe spent good money on worthless supplements for a diet that didn’t work.

Instead of anecdotal evidence and marketing hype, Moe should have looked for articles based on current research from sources you can trust to report research findings fairly and accurately. And, he could make sure the cited studies met scientifically rigorous criteria, like:

Hallmarks of Sound Science

Large Sample Sizes

If two out of four people lost weight on the diet, it doesn’t mean 500 out of 1000 would, too. Small sample sizes in a study simply don’t cut it. Big numbers are needed to support statistically significant claims.9


Studies should be designed with control groups and experimental groups, where subjects are randomly assigned to avoid any selection bias by researchers, placebo effects and other anomalies.10


The outcome of one study could be a fluke — but if results are replicated and repeated a few times, the study is more likely to be trustworthy. Meta-analyses are good for this — these are studies that review and analyze many similar studies. But if one isn’t available for your topic of interest, at least make sure that conclusions haven’t been drawn in a vacuum.11

Credible Sources

The sources matter, too. A study posted on “Frog-Legs-R-Us” might be suspect if it is expounding on the merits of reptilian drumsticks. Make sure sources don’t have a (marketing) reason to be biased.

The next time a claim sounds too good to be true, don’t repeat Moe’s mistakes. Make sure it’s not appealing to you for the wrong reasons, and that the so-called evidence is legit. Find research from a trusted, science-based source to get the real story. Avoid falling prey to fads, so you can be healthy for good!

Learn more from the National Institutes of Health about what to know when science is news.


1Hagura N, Haggard P, Diedrichsen J. Perceptual decisions are biased by the cost to act. Gold JI, ed. eLife. 2017;6:e18422. doi:10.7554/eLife.18422.
2Bunzeck, Nico & Duzel, Emrah. Absolute Coding of Stimulus Novelty in the Human Substantia Nigra/VTA. Neuron. 2006;51:369-79. doi:10.1016/j.neuron.2006.06.021.
3Beyens I, Frison E, Eggermont, S. “I don’t want to miss a thing”: Adolescents’ fear of missing out and its relationship to adolescents’ social needs, Facebook use, and Facebook related stress. Computers in Human Behavior. 2016;64:1-8.
4Hart W, Albarracín D, Eagly AH, Brechan I, Lindberg MJ, Merrill L. Feeling Validated Versus Being Correct:A Meta-Analysis of Selective Exposure to Information. Psychological bulletin. 2009;135(4):555-588. doi:10.1037/a0015701.
5Weisstein, Eric W. Law of Truly Large Numbers. MathWorld - A Wolfram Web Resource. Accessed May 19, 2018.
6What Is the Placebo Effect?. WebMD. Accessed 5/18/2018.
7Correlation does not imply causation. Wikipedia. Accessed May 18, 2018.
8Rao, Anita and Wang, Emily. Demand for 'Healthy' Products: False Claims and FTC Regulation. Journal of Marketing Research. 2017;54(6):968-989. doi: 10.1509/jmr.15.0398
9Zamboni, J. What Is the Meaning of Sample Size. Sciencing. Updated April 23, 2018. Accessed May 18, 2018.
10Helmenstine T. Control vs. Experimental Group: How Do They Differ? ThoughtCo. Updated August 04, 2017.  Accessed May 18, 2018.
11Why perform a meta-analysis? Comprehensive Meta-Analysis. Accessed 5/18/2018.