CNET logo Why You Can Trust CNET

Our wellness advice is expert-vetted. Our top picks are based on our editors’ independent research, analysis, and hands-on testing. If you buy through our links, we may get a commission. Reviews ethics statement

No. GMOs Don't Cause Cancer and 17 Other Health Myths You Can Stop Believing

Sorry, 10,000 steps a day isn't going to make you healthy.

Amanda Capritto
9 min read
Non GMO Organic French fries with organic food label.
Jena Ardell/Getty Images

Cracking your knuckles causes arthritis. Eating eggs gives you heart disease. Coffee stunts your growth. No, no and no again -- for decades, health myths like these have influenced consumer decisions, originating from obscure studies or the opinion of a then-influential doctor. Science has debunked much of this conventional wisdom that percolates as fact -- here are 18 of the most common health myths that everyone needs to stop believing right now. 

Myth: Exercising at night ruins your sleep


Feel free to work out at night if that's your jam.

Getty Images

The truth: Not for everyone. 

The advice of late-1900s exercise professionals would have you believe that exercising too late in the evening keeps you up at night. It's just not true for everyone: Researchers have found that certain nighttime exercises like yoga or weightlifting may have no impact whatsoever on your sleep quality, and for some people, exercising before bed can even result in better ZZZs

Read more: How to Get Better Sleep

Myth: Eating eggs causes high cholesterol


Go ahead and eat your omelet.

Getty Images

The truth: Eggs have almost no effect on your blood cholesterol. 

You, among millions of others influenced by the 1968 recommendation that adults should eat no more than three whole eggs per week, may have needlessly avoided eggs for the last 50 years. Scientists have since debunked the idea that eggs increase your blood cholesterol and heighten your risk for heart disease, and Harvard University's analysis of two 2018 studies even suggests that eating eggs can improve your heart health. 

Myth: You must drink 64 ounces of water each day

PhotoAlto/Odilon Dimier/Getty Images

The truth: Everyone has different hydration needs. 

Everyone knows the eight-by-eight rule: Drink eight 8-ounce glasses of water each day. This water intake recommendation stems from a very outdated -- in this case, centuries-old -- ideal. While based on accurate observations (water keeps you healthy), the notion that everyone needs exactly 64 ounces or two liters of water each day is wrong. Everyone has different hydration needs and should adjust their water intake accordingly based on their activity level and signs of dehydration.

Myth: 10,000 steps is the key to getting healthy

Sarah Tew/CNET

The truth: It's just not. 

Walking is fantastic exercise; it really is. But walking 10,000 steps a day is not enough to get healthy for most people. Exercise isn't one-size-fits-all, so it just doesn't make sense to blanket the general public with a step recommendation. 

I don't even get close to 10,000 steps per day (my average is about 4,000), but all my vital signs are healthy and I'm free of disease -- perhaps because I generally eat a healthy diet and meet the recommendations in the Physical Activity Guidelines for Americans.  

Myth: Six-pack abs are the epitome of health


Work your core, but focus on strength over aesthetic.

Getty Images

The truth: Six-packs are a scam.

Having six-pack abs does not make you the fittest person on earth, although it's totally valid to feel that way if you do have them. Forging 12 little divets into your stomach certainly requires hard work in the gym and mindfulness about your diet, but abs are more of a genetic quality than anything else. 

I, for one, could eat McDonald's once a day and maintain a toned stomach as long as I keep up with my workout schedule -- and I recognize that it's not that easy for everyone. 

Six-pack abs aren't something you should strive for, anyway, if your body type just doesn't support the goal: For some people, a six-pack means their diet is too restrictive or they're not taking in enough calories overall. Aiming for a strong core over a visible one is a better goal. 

Myth: Eating saturated fat directly causes heart disease

Getty Images

The truth: There are more factors to consider. 

Medical literature still contains much controversy about saturated fat and its relationship to cardiovascular diseases. For decades, public health agencies warned consumers about the dangers of saturated fat, and things really got turned upside-down when a groundbreaking 2017 study boldly proclaimed that saturated fat does not, in fact, clog the arteries. The study also stated that the risk of "bad" LDL cholesterol has been overstated. 

Since then, the scientific consensus has dissipated, and research about dietary fat and heart health is ongoing. The US Food and Drug Administration still recommends limiting (but not completely avoiding) saturated fat intake in the updated Dietary Guidelines for Americans, and to be safe, it's a good idea to follow their advice. 

Read more: Keep Your Heart Healthy With These Omega-3 Rich Foods

Myth: Organic foods are better for you

Getty Images

The truth: Evidence is extremely limited.

To date, there is just not enough valid scientific evidence that supports organic produce as superior to conventionally farmed produce. Studies have concluded that "there is some evidence for potential benefits of organic food consumption" but "considerable uncertainty/controversy remains on whether or to what extent these composition differences affect human health."

Organic produce is subject to different farming practices and tighter regulations than conventional produce (like no synthetic pesticides), but so far, that doesn't mean it's actually more nutritious. 

Many consumers also believe organic food to be healthier because it isn't produced with synthetic pesticides, but research isn't clear on that, either: One study concluded that "Organic foods convey lower pesticide residue exposure than do conventionally produced foods, but the impact of this on human health is not clear." 

Another study stated that analyses of human specimens (such as urine) after eating conventional and organic produce showed that there is a possibility that organic foods lower the risk of pesticide exposure, although the clinical implications are unclear. 

Myth: Natural sugars are better for you than refined sugar


All sugar, just in different colors and forms.

Getty Images

The truth: Sugar is sugar.

Coconut sugar, agave nectar, "raw" sugar, palm sugar, evaporated cane juice -- these are all sugar. They just sound healthier because they have fancy names. And hate to break it to you, but molasses and honey are just as bad as sucrose, or table sugar, when they're added to foods (and they still count toward your daily added sugar intake). 

Your body processes all simple sugars, like those above, the same way. There is one differentiation worth making, though: Sugar in fruit comes along with fiber, vitamins, antioxidants and minerals, which makes it more nutritious than sugar-laden snacks or candy. 

Myth: Coffee stunts your growth

Getty Images

The truth: Genetics determine your height.

For reasons unknown, this is a wildly common belief. According to Harvard University, "There is no scientifically valid evidence to suggest that coffee can stunt a person's growth." As for any other health risks you believe about coffee, those probably aren't true either: Coffee isn't linked to any medical conditions except for a slight, temporary increase in blood pressure. 

Myth: GMOs cause cancer


GMOs aren't as scary as you might think.

Getty Images

The truth: No, they don't.

Genetically modified crops are just not as scary as they're made out to be -- plain and simple. The wellness world might have you believe otherwise, but there is no scientific evidence that GMOs cause cancer (or any other health problems). A meta-analysis of long-term studies on GMOs concluded that "GM plants are nutritionally equivalent to their non-GM counterparts and can be safely used in food [for people] and feed [for animals]."

Plus, they can help farmers decrease pesticide use and increase crop yields and increase food security in developing countries. Science is good. 

Myth: Microwave ovens cause cancer

Getty Images

The truth: Nope.  

Microwaves heat your food: nothing more, nothing less. They do emit electromagnetic radiation, a form of nonionizing radiation similar to the radio frequency waves that come from your cell phone (which also won't give you cancer, by the way), but nonionizing radiation isn't known to cause cancer in humans because it isn't strong enough to alter the structure of cells. 

Plus, the radiation in microwave ovens is contained within the walls of the appliance, as long as yours is working properly. But even if yours does leak, the FDA imposes a maximum leak requirement on microwave oven manufacturers that is far lower than what would harm people.

Myth: Antiperspirants cause breast cancer

Woman applying underarm deodorant

Putting on deodorant is (hopefully) something we all do everyday.

Getty Images

The truth: No again.

Are we noticing the cancer thing yet? Apparently, everything causes cancer. This myth started coming about in the early 2000s, when studies like this one reported that applying deodorant to cells in a petri dish caused individual cell damage, and aluminum got called out as a potential culprit. But humans apply deodorant to the very outer layer of skin, not to individual exposed kidney cells. 

A review of studies later determined that aluminum in various forms is not known to cause cancer in humans. The American Cancer Society has also made its statement on antiperspirants and breast cancer: "There are no strong epidemiologic studies in the medical literature that link breast cancer risk and antiperspirant use, and very little scientific evidence to support this claim."

Also, the International Agency for Research on Cancer has a handy list of carcinogens classified by level of evidence that a substance can cause cancer, and aluminum is not on the list. Aluminum production is listed, but don't confuse the production of a metal with what is in your deodorant. 

Myth: Breakfast is the most important meal of the day


Eat breakfast, or don't -- whichever you prefer.

Getty Images

The truth: It's fine to skip breakfast.

The world will not end if you skip breakfast. Actually, the science behind intermittent fasting actually suggests that skipping breakfast could benefit you more than eating it. If skipping breakfast suits your lifestyle and your health needs, go for it: Just soothe your hunger before it turns into hanger. 

Myth: Cold weather causes colds

Getty Images

The truth: Weather alone cannot make you sick. 

Ah, a classic case of correlation without causation. Yes, more people get sick when temperatures drop, but cold weather doesn't directly make you sick. Possible explanations include: People spend more time indoors when it's cold out, and viruses spread more easily in close quarters; viruses spread more easily through dry air; and cold weather can temporarily impair your immune system

Myth: Everyone needs eight hours of sleep

Getty Images

The truth: Everyone is different. 

Eight is the magic number: Get eight hours of sleep and you'll wake up feeling like a magical forest fairy with boundless energy. For me, this is a big fat myth. I don't wake up feeling ready to leap out of bed unless I snoozed for a solid 10 hours. It's quite annoying, honestly -- I wish I was one of those superheroes who thrived on just six or seven hours of sleep. 

The point is: Everyone has a unique circadian rhythm that determines how much sleep is optimal for them. While seven to nine hours is still the standard recommendation for adults, you should treat sleep like hydration and exercise: Get enough so that you feel your best and keep your body healthy, but not so much that it starts affecting you negatively. You can always have too much of a good thing, even sleep

Myth: The sun is safer than tanning beds (or vice versa)

Getty Images

The truth: They both emit UV rays that cause skin cancer.

Tanning in the sun and in a tanning bed do the same thing: expose your skin to ultraviolet rays that cause premature aging and are known to cause skin cancer. There are arguments both ways -- the sun is safer, tanning beds are safer, but the American Academy of Dermatology knocks both sides down. Neither is good for your skin. 

Myth: Cracking your knuckles causes arthritis 

Getty Images

The truth: It's just the release of gases.  

Your joints may creak, crack and pop, but those noises typically have nothing to do with your risk of arthritis -- usually, it's just the harmless release of gases from synovial fluid, the fluid that lubricates your joints. 

If you have pain while cracking any joints though (or joint pain in general), it's worth getting checked out by a doctor, because you could have arthritis or another condition, such as tendinitis. 

Myth: Your body needs juice cleanses

Getty Images

The truth: Your body cleanses itself. 

Despite the popularity of juice cleanses to detoxify your body, your liver, kidneys and skin will get the job done on their own. Your body also eliminates waste and impurities through your digestive tract (poop, hello), your lungs and your lymphatic system. In other words, your body is basically one big filter for icky stuff. 

You can support your body's natural detoxing efforts by eating a healthy diet with minimal processed foods, exercising and working up a sweat, and drinking enough water. Juice cleanses or water fasts can do more harm than good, though: You just deprive your body of essential nutrients, both micro and macro.  

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.