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Exposed: The Top 10 Caffeine Myths

Avatar Nutrition Staff

September 22, 2017


For many of us, caffeine is life.

Whether you’re a black coffee drinker, a latte guy or girl, or you prefer a non-calorie caffeine-based energy drink, there are few among us who don’t ingest caffeine in some form.  So it makes sense to find out exactly what its effects are.

The myths flow thick and fast when it comes to caffeine, and you can never be sure what to believe. So let’s go through the top ten most common myths and debunk them one by one.


Myth #1 – Caffeine Dehydrates You

You’ve probably heard that caffeine has a diuretic effect, increasing urine output. But actually, most research suggests that a moderate daily coffee intake is in no way dehydrating whatsoever [1-3].


This may not be so surprising when you think about it, as water is the number one ingredient in most caffeinated beverages. Unless you’re taking caffeine in a pill, you will be consuming it in a liquid, which will far outweigh any theoretic diuretic effect.

In fact, caffeine has been shown to be just as good a hydration aid as water [4], and even when consuming caffeine in pill form, research has shown no major difference in level of urine output!

At the end of the day, caffeine isn’t exactly the powerful diuretic agent it’s been made out to be.


Myth #2 – More Caffeine Means More Energy

You know the feeling you get first thing in the morning when that initial drop of coffee hits your lips? It’s just like someone flipped a switch in your brain and put you in HD mode!

So it would stand to make sense that if a little caffeine can have this effect on energy and alertness, that more would be better, right? Maybe not.

According to the Journal of the International Society of Sports Nutrition:

“Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (≥ 9 mg/kg)” [5].

This means that for a person who weighs 150 lbs, the performance benefits of caffeine max out at around 200 – 400 mg.

It’s important to note that individual caffeine tolerance also may play a big role too [6]. We all probably know someone who can virtually be hooked up to an IV of coffee all day long and hardly gets even a buzz, whereas others take a half-shot Americano and are bouncing off the walls.

But for most people, a 3-6 mg/kg dose of caffeine will be more than sufficient. To establish your perfect dose, monitor your response to a fixed amount of caffeine, and to maximize its impact on sports performance, limit caffeine use to the pre-workout period.

“This means that for a person who weighs 150 lbs, the performance benefits of caffeine max out at around 200 – 400 mg.”


Myth #3 – Caffeine Works Equally Well for Everyone

Nope! Definitely not.

The literature appears to show that caffeine has a much greater effect on trained athletes than beginner to intermediate athletes.

In one study, both trained and untrained swimmers were given caffeine, but only the trained group saw a significant improvement in sprint performance [7]. In two other studies focusing on recreational cyclists, caffeine provided no greater performance advantage than water [8, 9].


Myth #4 – Caffeine Makes You Lose Weight

Research suggests that caffeine increases fatty acid use in exercise [10, 11] and raises metabolic rate and thermogenesis [12, 13], slightly increasing the number of calories you burn.

This sounds like a clear win for fat loss, but before you go ditching your diet for caffeine, let’s put things in perspective by taking a closer look at the numbers.

In one study, obese and lean women received 5 cups of coffee throughout the day, each containing a 4 mg/kg dose of caffeine (based on normalized body weight). On average, the lean women burned 174 extra calories over the entire day, while the obese women burned an extra 98 calories [14].

On the surface, this may sound like a lot of calories, but the amount is much less impressive when you consider the dose of caffeine needed. To have this effect, a 130-pound woman would need to consume a daily total of nearly 1.2 grams of caffeine! That’s about 14 cups of your average coffee brand each day just to give you one extra cookie! Not a great trade-off when you think about it.

Also, this is a pretty absurd amount of caffeine and one that is borderline dangerous even when distributed over a 24-hour period!

Bottom line: Caffeine isn’t exactly the fat-busting ingredient it’s been made out to be. Calories in versus calories out is still the most fundamental factor in losing body fat, and any metabolic effects are relatively small.


Myth #5 – Coffee is Better Than Other Caffeinated Beverages for Performance

Coffee lovers vs. Monster drinkers—It’s a battle that will be hard-fought for years. Leaving the taste test aside, there’s a debate between which has the greatest effect on performance.

Well the results are in, and it seems the winner is…neither!

A recent 2016 study found that the effects of caffeine absorption between coffee and energy drinks was negligible, and the speed at which the caffeine was consumed, along with the temperature and the beverage itself didn’t really matter [15].

The main consideration here is personal preference, as well as how many calories your caffeinated beverage contains.


Myth #6 – Caffeine is Addictive

We might think we know people who are addicted to caffeine, and while it’s often referred to as a drug, caffeine isn’t exactly addictive.

Inconclusive research has shown that caffeine dependence can potentially be a concern [16], but it’s far from being a narcotic. Remember, there is a difference between a psychological dependence and a chemical addiction! As of yet, they haven’t started a ‘coffee drinkers anonymous’ or opened up the first latte rehab center.


Myth #7 – Caffeine Cures Hangovers

After a heavy night on the town or hitting the clubs, a strong cup of joe probably will make you feel more alert, but it’s no miracle hangover cure.

In fact, while drinking a caffeinated beverage might help combat alcohol-related dehydration, the caffeine itself tends to narrow blood vessels and increase blood pressure, which could possibly make a hangover worse.

If you’re accustomed to drinking coffee each morning, go for it, but don’t expect it to make your hangover disappear.


Myth #8 – Caffeine Causes Tooth Decay

Caffeine itself has no impact on tooth decay, but coffee is slightly acidic, leading some people to declare that it rots your teeth.

Although there is little evidence to support the notion that plain black coffee will put your teeth at risk, sipping endlessly on coffee sweetened with a boatload of sugar may be another story. Ironically, coffee contains anti-bacterial agents, which, if anything, aid to prevent tooth decay!


Myth #9 – Caffeine Causes Osteoporosis

This is remarkably similar to the myth that high-protein diets cause osteoporosis, and stems from the fact that it can decrease the absorption of calcium into the bones slightly.

Here though, it boils down to theoretical science versus real-world application.

Does coffee leach calcium from bones?


But the amount is so minimal that it couldn’t possibly be a cause of osteoporosis on its own, and even adding just a drop of milk to your coffee, or consuming any dairy products at other times during the day would grossly outweigh any loss of calcium from drinking coffee.


Myth #10 – Natural Caffeine is Superior to Synthetic

Ah, the good old buzzword brigade again.

Marketers are clever, and it’s easy to make natural caffeine, harvested from special berries in a remote jungle somewhere sound healthier, cleaner and more attractive than caffeine produced closer to home.

However, as the chemical structure is the same, the effects on the body are the same too.

Even if your caffeine does come from some super amazing, superfood style plant, remember that once the compound is isolated from its source, it loses any benefits associated from said plant too. Essentially you’re paying more (often 5 to 10 times more) for exactly the same product.


Caffeine: Is It for You?

While there are plenty of myths surrounding caffeine, it seems that in terms of energy and performance (and to a smaller degree fat loss), caffeine is a winner.

It’s even been shown to have positive effects when it comes to protecting from dementia [17] and reducing the risk of depression [18].

You needn’t stress too much over the minute details though, as this article has hopefully demonstrated.

Provided you stick to a moderate caffeine consumption, don’t drink so much you feel unwell or become immune to its effects, and keep an eye on your performance and stress levels, you don’t need to follow any strict guidelines.

[1] Maughan RGriffin J. Caffeine ingestion and fluid balance: a review. Journal of Human Nutrition and Dietetics. 2003;16(6):411-420. doi:10.1046/j.1365-277x.2003.00477.x.
[2]  Fiala K, Casa D, Roti M. Rehydration with a Caffeinated Beverage during the Nonexercise Periods of 3 Consecutive Days of 2-a-Day Practices. International Journal of Sport Nutrition and Exercise Metabolism. 2004;14(4):419-429. doi:10.1123/ijsnem.14.4.419.
[3]  Greer F. Myth buster: caffeine does not exhibit a diuretic effect during exercise performance. Indian Journal of Medical Research. 2010;132:11-13.