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10 Common Keto Myths (and Why They're FALSE!)

As champions of the keto diet and lifestyle, it’s part of our mission to debunk the nonsense that keto is just another flash-in-the-pan fad, and look at some of the inaccuracies you might find when doing your keto research or discussing this way of life with your peers. We’ve rounded up 10 popular keto misconceptions, and we’re gonna set the record straight, right now. Here we go:

1. Switching to a keto diet will make you sick

We cover this in other posts, too, but it’s generally understood that upon starting keto, some people have an adjustment period that doesn’t feel all that great. Commonly termed the “keto flu,” as the body transitions from carb-burning to fat-burning, symptoms like headache, fatigue, muscle aches, etc., can and do arise. This isn’t a bad thing, actually—it tells us that your new eating protocol is working! 

The so-called sickness that comes with going keto is short-lived, and depending on your body, you can get through it pretty quickly, or bypass it completely. (Supplementing with electrolytes can be a major help in avoiding the keto flu, too.) So keto doesn’t make you “sick” at all—your body is simply going through chemical changes that cause some temporary discomfort.

Incidentally, this “flu” isn’t just a keto thing—it used to be called the Atkins flu. This process of the body adjusting to less carbohydrates has been understood for over 20 years, and is not exclusive to ketogenesis or the keto diet alone.

2. Keto causes insomnia

We’re not really sure where this claim comes from. Frankly, we at Keto Function have experienced much-improved sleep on a ketogenic diet. If you look at the science, indicators point to better sleep, or more time in deep sleep, for people on high-fat and high-protein diets versus those on high-carb diets.

There was also a 2017 survey in the Journal of Insulin Resistance that debunks this nonsensical idea. Of 1,580 low-carbers, more than 11% said they were using sleep aids before starting their low-carb diet, but only 5% reported using them after they started. Seven in 10 said their sleep improved after going low carb. We don’t believe in messing with quality zzzs. We also don’t believe—with good reason, clearly—in this “keto-somnia” lie.

3. You’ll always be hungry on keto—it’s a “diet,” right?

The word “diet” has some unpleasant connotations—think restriction, cravings, hunger, dissatisfaction—but really “diet” by definition is just a way of eating. Most people think of going on a diet as a way of trying to correct or fix bad eating habits that have caused them to gain weight over time. Over the years, fad diets have perpetuated this idea of “diet as restrictive,” which you can distill down to an even more personal notion that “’diet’ means I’m bad/there is something wrong with me.” This isn’t a very positive way to view your relationship with food, or yourself, is it?

This is why we prefer to look at keto as a lifestyle choice, a way of eating that promotes physical health and doesn’t feel restrictive. And this “diet” doesn’t feel like the ones that many people associate with trying to lose weight. Keto doesn’t limit caloric intake—as long as you stay within your macros and keep carbs in the right range, you can eat as much as you want. So you’re not going to be feeling hunger pangs for long periods of time. And let’s take this a little further—in this piece from Thrive Global, you can read all about how satiety is the key to weight loss (or gain), and that people generally get fat because they eat foods that are less filling. Can you guess which ones those are? The refined carbohydrates, generally speaking. In fact, proteins are the most satiating foods. So if you’re taking in adequate protein and fats on keto, you should not be going hungry!

Let’s go back to the Journal of Insulin Resistance for a sec—of those 1,580 low-carb survey participants, pre-low-carb diet 9 out of 10 of them said they felt extreme hunger between meals. Post-low-carb diet, less than 4% reported feeling hungry. This is part of why going keto is much more than a diet—it can become a sustainable lifestyle change because it keeps you feeling satiated, so you’re not giving in to constant cravings.

    Ketogenic food pyramid


    4. Keto causes acne

    Here’s the thing about this—acne is an inflammation problem. And carbs/sugar are responsible for way more inflammation than healthy fats and proteins! Especially if you’re keto-ing on a steady intake of healthy non-animal fats, a low-glycemic, high-fat diet may in fact help conditions like acne!

    A review by Italian researchers indeed suggests that because keto keeps insulin and IGF-1 levels in check, it has a positive (in this case a lessening) effect on inflammation and associated conditions. Take that, pimple rumors!

    5. The brain needs sugar/glucose to function properly

    People who are down on keto tend to overstate this claim, causing unnecessary confusion. Your brain does in fact need glucose. But here’s the thing: It only needs somewhere in the ballpark of 30-50 grams of glucose per day to function optimally. And your body can manufacture this glucose from the protein you’re eating, too, through the process of gluconeogenesis. So you don’t really even need to consume carbs to get adequate glucose for your brain. Your brain is also quite happy to use ketones for fuel. In a keto-adapted person, the brain can get 75% of its fuel from ketones and the rest from synthesized protein. Take it from Mark Sisson, legendary founder of Mark’s Daily Apple:

    "If you’re on a very high fat, very low carb diet – like a traditional Inuit diet – your brain will eventually be able to use fat-derived ketones for about 50-75% of its energy requirements. Most ketones are produced in the liver, but astrocytes in the brain also generate ketones themselves for use by neuronsYou think we’d have that kind of set up in our brains if ketones weren’t useful to have around? If all we could do was burn glucose up there, what would be the point of even having localized ketone factories?" 

    The bottom line is that keto naysayers need to do their homework on this point.

    6. Keto is dangerous because it elevates cholesterol, which affects heart health

    There has been such seesawing of information about cholesterol over the years that it’s no wonder this argument is full of holes. One needs to understand first and foremost that there are two types of cholesterol—the “bad” LDL, and the “good” HDL. (There are also issues with this categorically good/bad dichotomy, but that goes beyond the scope of this post.) It’s also important to understand that LDL influenced by diet hasn’t been shown to have any effect on cardiovascular outcomes—even when LDL decreases.

    Now let’s talk about this as it relates to keto. One study of 447 subjects showed that low-carb diets not only assisted in weight loss, but actually improved overall cholesterol levels! Another analysis of 17 different clinical trials showed low-carb diets protected people from cardiovascular risk. Another study revealed that low-carb dieters had lower overall cholesterol than low-fat dieters after one year. Keto has been shown to not only raise HDL (the good cholesterol), but improve blood pressure and other cardiovascular risk factors, too. We recommend that you always monitor your progress in keto, especially at first, and consult your doctor before embarking on the keto journey if you have any medical conditions. But on the whole, keto should improve both cholesterol and heart health. Myth busted.


    7. Keto is dangerous because it can cause ketoacidosis

    As we’ve discussed in other posts, the keto diet is designed to put your body in ketosis and keep it there, creating an optimal fat-burning state in which you’re swapping carbs/sugar as fuel for fat/ketones. Ketoacidosis is extremely dangerous and potentially life-threatening, a condition where the blood becomes highly acidic. Extremely high ketone levels can cause this condition, but it’s highly unlikely that anyone following the keto protocol and sticking to their macros could ever reach these levels.

    Making sure you’re eating the right amount of protein, and not overdoing it, can help keep levels in check, and a healthy keto-er shouldn’t have any trouble. Generally, ketoacidosis is only a real danger as a complication of diabetes where the body isn’t getting enough insulin while ketone levels become elevated.


    8. Keto can only be done for a short time

    At Keto Function, we really don’t see keto as a diet, but more as a lifestyle. We’re not just keto enthusiasts because we’re selling products, either—this is our lifestyle, and we’re passionate about sharing it with the world because it is in fact sustainable. No diet or lifestyle is for everyone, but if you find that keto feels right for you, you just might also find that it’s not only about getting past a weight loss goal or some other specific reason, but that you feel amazing and can’t imagine going back to a carb-heavy way of life. We certainly can’t, and we’re not alone.

    9. Weight loss on keto is short-lived

    There are those out there who would have you believe that going keto for weight loss will only help you for a quick sprint, not the long haul. But again, studies show this to be incorrect. Some truth bombs for you: One meta-analysis published in the British Journal of Nutrition (an analysis of multiple studies and their results) showed that people on a low-carb ketogenic diet lost more weight in a year than those on low-fat diets. Notice how we said “a year”? Yeah, this diet is sustainable.

    How about this one from—once again—the Journal of Insulin Resistance? Three in four of those 1,580 survey respondents reported dropping 10 pounds or more on keto and a third reported 30+ pounds lost. Our favorite stat: Six in 10 who were on keto for two years or more reported losing 20 pounds or more. If it wasn’t sustainable long-term and wasn’t getting weight loss results, why would these people go keto for two years?

    10. Keto isn't good for athletic or super active people, who need more carbs

    There has been limited evidence that keto can be associated with a small decrease in anaerobic performance, and so the going myth is that keto is bad for athletes as the lack of carbs will make them tire more easily. The truth is that it really all depends on your specific physiology and the kind of exercise you’re trying to do. If you’re training within reasonable skill and fitness levels, your keto-adapted body can use fat for fuel as efficiently as carbs, plain and simple.

    Studies have shown that a keto diet has actually helped athletes—serious ones. If it’s good enough for LeBron, it’s probably good enough for you, too! And check this out: one study revealed that after 12 weeks on keto, endurance athletes actually increased oxidation and sprint power, and performed better on a “critical power test” than carbed-up athletes!

    There’s also a notion that keto will make you lose muscle and reduce lean body mass. Erroneous! Check out this three-month study on CrossFit participants, proving keto didn’t touch their hard-won gains.

    Final Thoughts on These Common Keto Misconceptions

    We hope that all these keto misconceptions are resolved for you at this point. But if you’re still wary of starting keto or have had a rough experience with it in the past, we’d love to hear more about where you’re at. Feel free to reach out to us with questions at any time, we love hearing from the keto-curious. We’ll have more to say on some tougher topics in future posts (like looking at keto and diabetes, how keto affects your gut health, and much more), too.

    And if you’re ready to start a keto diet, or give it another try, we’ve got lots of tools to help get you into ketosis, avoid the keto flu, and stay healthy whether you’re doing it for a short time or making it a lifestyle choice!


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