Why does health advice keep changing?
Table of Contents
It’s common to feel frustrated by the seemingly constant swings in science - one minute you aren’t to have any eggs, the next you should be eating eggs every day.
What’s someone looking for answers to living a healthy life to do?
In this article we explain why science can change depending on how the experiment was done, and what this means for you.
This is why it’s important to find a source (like aldora!) that combines the latest research with real-life experience in our guides, helping you sort out what is best for you.
4 Ways Science Varies
One of the biggest reasons why science sometimes contradicts itself is that it can be done in many different ways, meaning that what is found is (not unsurprisingly) different as well.
Science can be different in 4 big ways:
Who was studied (the people)
What was studied (the intervention)
What it was compared to (the comparison)
What they looked for (what was measured)
When people on social media or other places don’t understand this nuance, you end up with conflicting advice because they are trying to combine two very different studies into one “answer”, which isn’t right for you.
We’ll unpack each of these variations in the following sections.
Always ask yourself: who was studied, where, and when; what did they do, for how long; what did they compare it to; and what outcomes did they measure?
#1 Who was studied
The people taking part in a study or experiment are not always the same as you or I, and they are often different from one study to the next.
The people (called “participants” in a study) might differ in:
personal factors (like their age, race, gender, sex, medical issues, medications used, careers, education, income, etc), or
in situational factors (like where they live, whether they were recruited in hospital or in a community clinic, what year it was, etc).
For example, a study looking at a “healthy diet” for 10 year olds living in rural Ontario in the 1980’s would probably find very different conclusions than a study looking at a “healthy diet” for 80 year olds living in New York City in 2024.
If the headline simply says “a healthy diet can prolong life” - we’ve really got to know more about who was actually studied???
KEY TIP: To find the right science for you, look at studies that were done on people who are similar to you.
Remember: although science is getting better at including more diverse populations, these populations still tend to be younger and healthier than the average person living in their 70’s, and minority groups are often underrepresented.
This is one of the fundamental reasons why you want to discuss research with a healthcare professional who has seen a lot of people like you, so they can interpret research findings to your specific circumstances.
Always look at who was studied. Ask yourself - is this group similar enough to me in the ways that are important?
#2 What was studied
Different studies looking at the same activity, drug, device, or service (called the “intervention), can still do slightly different things with that intervention, meaning the outcomes will (not unsurprisingly) be different as well.
This could be in:
what the intervention itself includes
how much of it was used
how often it was used, and
over what time frame it was given
For example, a study looking at a “healthy diet program” that involves telling people to increase the amount of healthy food consumed over a 7 day period might find different conclusions than a “healthy diet program” that involves a tailored meal plan, a dietician consultation, weekly telephone reminders, and pre-made meals delivered to your home, all over a 6 month period.
Once again, when the headline reads “a healthy diet program can prolong life”, we need to know what was actually in that healthy diet???
KEY TIP: When deciding whether to use a study in your own life, make sure to look at the details of what was actually done (what, how much, how often, over what time frame).
This is the only way to know what you are supposed to do if you want the same results (assuming the people were similar to you!)
It’s also the only way to know what the longterm benefits and risks might be, or in some cases, know that we don’t know what the longterm benefits and risks are if it was only studied for a few months.
What exactly did the study do? How much, how often, and for how long?
#3 What it was compared to
The conclusions of a study often depend on what they compared their intervention to (called “controls” in studies).
Studies can compare their new innovation to:
placebo (a “fake” pill that is made of sugar, not a medical drug)
the current standard of care
nothing
For example, a study comparing exercise to no exercise might find different results than a study comparing exercise to ozempic, or comparing exercise to a high-calorie diet.
In each of these scenarios, the benefits of exercise might appear more or less than in the others.
KEY TIP: Find a study that compares the new intervention to what you are already doing. That could mean comparing it to nothing, or comparing it to a drug or something else that you are already on.
That’s really the only way to know the magnitude of the benefit that you could expect to get (assuming that the population is similar to you!).
Did the study compare the new idea to what you are already doing?
#4 What they looked for
If the scientists measured different things (called “outcomes” in the study), they will (unsurprisingly) report different findings.
Studies can look at:
different outcomes (mortality, falls, heart attacks, stroke, hospital admissions, healthcare costs, quality of life, caregiver burden etc)
Studies can also look at the same outcome, but measure it in different ways:
surrogate end-points (for example, looking at the amount your blood sugar levels are reduced, and extrapolating that to suggest this would result in less heart attacks and strokes, but we don’t actually know if it would, because it wasn’t measured)
different tools (for example, measuring “cognitive decline” using the MMSE, MoCA, RUDAS, ADAS-COG, etc - each have different elements they look at and a different total score).
composite outcomes (for example, considering “falls”, and “broken hips”, and “any broken bone” as one outcome of “fracture reduction”).
using numbers, or asking questions (i.e. doing patient interviews to understand the experience and real-world outcome of the intervention, or measuring labs, survey responses, and “hard” outcomes that have been reduced to a single number).
There are even more ways it can vary, but already you can start to see how complicated it gets, and how studying a complex intervention like changing one’s diet could be hard to compare across studies!
KEY TIP: Look for a range of studies that look at all of the outcomes (or as many as possible) that are important to you for a particular intervention.
The more studies you look at, the more you’ll get a sense for how this intervention impacts people like you across a variety of outcomes.
Of course, this can get challenging when these outcomes are not studied in the same population, same intervention, or with the same comparison, as it can become hard to compare the outcomes.
At this point, I hope it is clear that “science” is a lot more varied and complex than the single-word implies!
That brings us to the next part - finding the sweet spot for you.
What outcomes did the researchers choose to look for? How did they measure it? How did they report the outcomes to you?
Finding the Sweet Spot for You
Because of the variability of science, taking one study and applying it to your personal situation is more complected than it might first appear.
For a study to be 100% applicable to you, every person in the study would need to be a clone of you, living the exact same life, doing the type of intervention that you would be able (and willing to do), and for an outcome that you care about.
Obviously, this isn’t the case for anyone, and so what science gives us is an approximation of what will work for you.
The more studies we have in the same population as you, across different contexts, the more certain we can become that the intervention will work for you, but it is always a dance of research vs reality.
All research is still an attempt to point us in the right direction, but the ultimate decision of whether to try a new intervention or not requires some conversation about risks, benefits, probabilities, and choice.
KEY TIP: Ask about risks, benefits, and likelihood or probability of the desired outcome happening for someone like you.
You’ll soon find that there are some things in medicine for which we have overwhelming evidence work and are good for almost everyone (like taking antibiotics for a blood stream infection). These are the things you always want to say yes to.
But there are other things in medicine that we do our best with approximations of reality, like deciding what blood pressure is best for you, which requires us to adjust our understanding and our management as science evolves.
Having a healthcare provider that works with you is your best bet of finding personalized success.
In closing…
Science is the best method we have for figuring out what is going on in the world, but it is not perfect.
Science simply can’t study every single unique person, or every single type of intervention, or compare it to everything else in the world, or measure all the possible outcomes.
This isn’t a failing of science - this is a reality of the universe.
It is our job to take what it has done and make the best of it, by applying it to our lives when it makes sense, and looking to find the sweet spot where we get the benefits that matter most to us.
Disclaimer: The content on Aldora Health is for educational and informational purposes only and is not intended to substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. For more read our Terms of Use.