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  • Writer's pictureSean Fitzgerald

5 nutrition myths and what you need to know instead

Updated: Apr 28, 2021

If you’ve ever had a conversation about nutrition then chances are you’ve heard a nutritional myth… or 10. Given the fact that we all eat food (because, well, survival and all that), we all tend to have opinions, ideas, and biases around nutrition. More than ever, given the explosion of misinformation and fake news online, this tends to manifest itself in the form of myths and misconceptions.

On the surface, this can seem harmless but digging a little deeper, in certain situations for certain individuals, false nutritional information can be just as harmful as false information in other areas.

But before we get into some of the worst nutrition myths, let’s take a closer look at why they occur. Most misconceptions start out with some degree of fact or truth to them. Over time, these facts become twisted into the myths that we often see sticking around for years. There are many reasons why this happens. Let’s look at four of them:

1. Misunderstanding or misinterpreting the results of scientific studies.

You may have heard the term “correlation does not imply causation,” but what does it really mean? Well, when something directly results in something else happening, that is causation. Correlation, on the other hand, is when there is a link or relationship between two things, but that doesn’t necessarily mean that one causes the other. A popular example of this is the fact that there is a relationship between ice cream sales and murder rates. On average, in months where ice cream sales are higher, murder rates are also higher and vice-versa. Does this mean that more ice cream sales lead to more murders? Of course not. It’s just one of many correlations that occur. Unfortunately in nutrition this can happen in many different scenarios, some examples of which I will cover later.

2. People are easily convinced by myths because they want to be.

By now, making an X-Files reference is as topical as outlining the works of Leonardo DaVinci. But a key part of the 90s sci-fi show was the idea that people could only open their eyes to the truth of the world around them because they wanted to believe. The same is true with nutrition. It makes sense too. I mean, if someone tells you that you can just pop a diet pill for weight loss, of course that sounds a lot easier than reducing your calorie intake and exercising more right?

3. The media accidentally, and deliberately, spread misinformation.

As I mentioned previously, many myths start out with some basis of fact. But media outlets, social media platforms, and even blogs just like this one can twist scientific evidence to paint a very different picture from the truth. For example, we know that many nutrition studies are carried out on rodents. We also know that these results are not replicated in humans more often than not. However, when it emerges that turnips seem to cause cancer in rats, you can bet your €10 salad that you’ll see a headline saying “Scientists confirm eating turnips causes cancer.” Adopting some critical thinking, and reading past the headline, is crucial when engaging with nutrition information online.

4. Nutrition findings are often self-reported.

What’s best for one person is not always best for another. For example, Sue embarks on a diet which she successfully loses weight on. After struggling for years to do this, she feels she has now finally found the answer so she swears by this diet and passes it onto her friends. Mary, who happens to be quite a bit less active than Sue, follows the diet exactly as Sue did but sees no results after a month. Unfortunately, neither Mary or Sue are aware of the principles behind weight change and only see this method as the way to achieve it. Sue only has good intentions but she has now unknowingly shared a nutritional myth/misconception with her friend group.

So now we’ve covered the main reasons why nutrition myths occur, let’s explore a few of the most widely shared and believed myths and pick apart exactly why they’re untrue.

Myth 1: Gluten is bad for you.

In recent years, the gluten-free movement has gained some serious traction. It’s relatively easy to see why. Overconsumption of palatable, high carb foods contributing to weight gain means that “it must be the gluten.”.

Spoiler alert: It is not, in fact, the gluten. If anything, slamming gluten as the cause of every health defect is a bit of an insult to diagnosed Celiacs. Gluten is merely a naturally occurring protein. Removing it from your diet when you don’t need to really limits your food options and won’t necessarily mean you’ll have an automatically healthy diet as a result.

Lis et al. (2015) concluded: “A short-term GFD had no overall effect on performance, GI symptoms, well-being, and a select indicator of intestinal injury or inflammatory markers in non-celiac endurance athletes”

And in fact, removing gluten for true Celiacs will likely cause weight gain* as they are removing the disruption to their digestive system, meaning they will better digest their food, and therefore more of the calories from it.

“Of patients compliant with a gluten-free diet, 81% had gained weight after 2 yrs”

Dickey & Kearney (2006)

Myth 2: Artificial sweeteners cause negative health effects.

In modern discourse, the likelihood of hearing that artificial sweeteners are unhealthy is about as likely as someone commenting on the weather. The fact is, though they are still being heavily studied, there’s currently no evidence to suggest that artificial sweeteners are harmful to human health. As a caveat, if evidence were to emerge at any point indicating harm caused by sweeteners, I would change my stance on them in that instance. However, everything that’s currently out there points to a perfectly high safe upper limit for daily sweetener intake.

One argument often made is that sweeteners cause an insulin response just like sugar. A systematic review of many studies on this determined that:

““There was no consistent evidence that intense sweeteners cause insulin release or lower blood sugar in normal subjects.”

Renwick & Molinary (2010)

Some studies have shown an association between sweetener consumption and those with a higher BMI, but there is a simple reason for this. Those studied are often people attempting to diet, therefore they are choosing sweeteners over sugar in an effort to aid in their weight loss efforts. This does not mean that sweeteners have caused their higher BMI.

For those aiming for weight loss, replacing caloric foods/drinks with low calorie sweetener alternatives works. They help to reduce cravings and increase fullness.

Another argument we will often hear is that sweeteners are unhealthy due to the chemicals they contain but there’s one key thing that people forget with this: Literally everything is comprised of chemicals.

If I offered you some Dihydrogen Monoxide to drink you might be a bit alarmed and refuse to take it. However, if I offered you some water to drink, you’d likely accept it without a second thought. If I told you DIhydrogen Monoxide and water are the same thing, you might realise that people use official and scary sounding terms to make things seem worse than they are and ultimately profit from the fear they can create.

The only people who may benefit from limiting their consumption of artificial sweeteners are the few who notice digestive discomfort from having them. This appears to affect a small minority of people and for those, avoiding or reducing their sweetener intake does seem to be helpful.

Myth 3: Organic foods are healthier than non-organic.

This is another one that sounds very credible on paper but really doesn’t have the research to back it up. Referring back to the point made about chemicals in sweeteners, stating that non-organic food is unhealthy due to the chemicals used on them is a null and void argument. Take, for example, the ingredients of an organic banana. Nothing added, untouched by anything except the surroundings it grows in. And still there are numerous individual chemical ingredients that make up a banana. The same applies for any other food.

Now, while organic foods have been found to have 30% less pesticide residues than non-organic, the levels found in both were within the allowable safety limits. This means, you guessed it, non-organic foods will have no negative health effects, while choosing organic won’t really offer any additional benefits to you.

Another study found that organic chicken and pork were a third less likely to contain antibiotic-resistant bacteria than conventionally raised animals, however, the bacteria that cause food poisoning were equally present in both. Dangour et al. (2010)

Whether you eat organic or non-organic foods is up to you, but know that whichever you choose won’t have a bearing on your health.

Myth 4: Eating too much protein will damage your kidneys.

Personally, I find this quite a frustrating myth. Anyone with sound nutritional knowledge will tell you that the benefits of eating enough protein are endless — it’s far from just something needed by those who lift weights — but myths like this one wreak havoc on that message.

A quick Google search will give 100s of results citing protein as detrimental to renal health and this really doesn’t help the cause. The truth is:

  • There were no reports of harm to renal function due to protein consumption, even in populations at higher risk of kidney disease. Martin et al. (2005)

  • Weight loss achieved by following a high protein diet reduces the risk of negative renal function. Wycherley et al. 2010; Tay et al. (2015)

It’s like saying doing too much exercise will wear out your lungs. So say it loud, eating lots of protein will not wear out your kidneys.

Myth 5: You cannot eat junk foods if you want to lose weight or maintain good health.

This final myth is the reason that people all around the world embark on miserable, restrictive diets that last about five days before crashing and burning. The reality is this: There are no unhealthy foods, merely unhealthy diets

Granted, getting the majority of your food from whole, minimally processed sources is a good idea. But, once you stay within the confines of your calorie requirements, there’s nothing wrong with dipping more into the realms of less nutrient dense foods every now and then, even if it’s something small everyday.

Junk foods tend to be hyper palatable and calorically dense but having them occasionally may actually benefit your health from a social and enjoyment point of view.

Labelling foods as ‘bad’ does nothing but create a mindset of guilt around food and implies punishment is needed e.g “I ate these jellies, that’s a bad thing, I’m a failure, I need to now restrict myself as punishment.” We see a similar effect from calling meals “cheat meals” when the truth is that they are, in fact, just meals.

An approach I like to take is the 80/20 method of getting 80% of your food from nutrient dense sources like lean meats, fruits, vegetables, nuts, seeds, dairy, wholegrains, etc and allowing wiggle room with the other 20% to come from the fun stuff. What is life without a bit of chocolate? And the beauty of it is you can make just as good progress that way. And, more often than not, better progress due to actually being able to stick with the approach.

Don’t feel guilty about succumbing to these myths.

So there we have it. Five nutrition myths which you may have succumbed to in the past but don’t feel bad. An entire industry has been created to make you fall for them. However, now you have the awareness to not trip over them again.

Just remember:

  • Gluten only needs to be avoided if you’ve been diagnosed with Celiac disease.

  • There is no evidence that artificial sweeteners need to be avoided, in fact they are a useful aid in weight loss for many.

  • Organic foods are no healthier than non-organic foods.

  • A high protein diet will only be of benefit for your health and will not damage your kidneys.

  • You can include any foods as part of any diet and still make great progress. Moderation is everything.

I hope this article helps you in approaching nutrition with a more critical perspective. Please do share it with anyone who you feel may benefit from it. Together we can defeat nutrition myths once and for all.

Note: Much of the information in this article has come from a lecture from my nutrition qualification from Mac Nutrition Uni. More information on MNU can be found here:


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