Part of my job as a registered dietitian is to keep up with the latest nutrition research and trends. I read and interpret nutrition research so that you don’t have to, and so that you can receive safe nutritional care. While working on my undergraduate degree, we hit the basics on what to look for to identify strong and reliable research studies. In my master’s program, we hit this even more in detail. This is so that I can provide my clients with safe, evidenced based recommendations top help them reach their goals safely and realistically.
I have noticed recently several posts on social media of research articles being posted like they are gold. After reading the articles I found that many of them have very small sample sizes (<20 participants), they were pilot studies, the participants volunteered and were not randomly selected, there was no ethnic or gender variation, and the authors had conflicts of interest with companies they worked for. Many people see the title of a research article stating that a certain diet had a positive effect on weight loss or some other disease process, and they think that’s it. If a research article says it worked then it must be good for me, right? It depends. The study may still be in the beginning stages and we don’t know enough yet to make a recommendation based on the results. However, if the results are promising, then further research will likely be conducted on the topic.
So how do you know if it is a good study? There are many different factors that play a role in determining a “good study”. These are a few of the things I look for when looking at a research article to know if it is a strong study:
Large population size – I look for studies with >200 participants. Studies with a population between 20-199 are still okay, they just have to be interpreted carefully. Any study with <20 participants is likely to have false positive results.
Ethnic and gender diversity – Studies with a more diverse population are going to be stronger studies for the general public. However, sometimes we like to see the effects of a certain interventions on a specific gender or race.
Randomized-controlled, double-blind clinical trial – These studies are considered the “gold-standard”. The participants are randomly selected and neither the participants or the researchers know which group is receiving which intervention. This removes any bias from the researchers and it reduces the likelihood of the placebo effect from the participants. Not all studies are able to be conducted as a double-blind trial because of the intervention, but if the participants are randomly selected it is a stronger study.
Pilot study – Pilot studies are studies done on a very small scale to “test the waters”, so to speak, before a larger study can be done. The goal of this type of study is not done to answer the question of “will the intervention work”, it is done to answer the question of “can I do this?” Results from pilot studies should be taken with a very small grain of salt.
Conflicts of interest – Do the authors have any conflicts of interest? Where did they receive funding? Did the National Beef Association provide funding to conduct a study to show that beef does not increase the risk for heart disease? These are important questions to ask when looking at a study. If there are any conflicts of interest, whether it be from a company an author works for or the source of funding, there may be bias in the results. Food companies like their products to show positive results and the studies that do not show positive results are less likely to be published with their funding.
These are the main items I look for when reading through a research article. It may seem like a lot, and sometimes it is, but this is why registered dietitians, nurses, doctors, etc. are trained to interpret and condense research so you don’t have to. However, I still think that it’s good for everyone to know the basics of reading and interpreting research so they don’t fall into a trap. The next time someone posts a research article that seems too good to be true, skim through it with these items in mind and see what you think.