Busting Myths: From Childhood Tales to Fitness Lies We Still Believe

We all grew up hearing some pretty strange myths—some meant to keep us in line, others just passed down through generations without question. Remember when we were told that if we swallowed gum, it would stay in our stomachs for seven years? Turns out, that’s far from the truth—our bodies can’t digest gum, but it passes through like anything else. Or what about the warning that cracking our knuckles would lead to arthritis? Studies have shown that while it might annoy the people around us, it won’t actually damage our joints.

Just like these childhood myths, the fitness world is full of beliefs that sound true but are actually holding us back. Let’s break down some of the most common fitness myths and set the record straight—with science.

Fitness Myths You Need to Stop Believing

“Lifting weights will make you bulky.”

This is one of the biggest misconceptions, especially among women. In reality, building noticeable muscle mass requires high-calorie intake, progressive overload, and significant hormonal support (especially testosterone). Women naturally have lower testosterone levels than men, making it much harder to bulk up.

Science Says:
A study published in the Journal of Strength and Conditioning Research (2014) found that resistance training significantly improves strength and muscle tone without causing excessive hypertrophy (bulking) in women. Instead, it leads to better fat loss and metabolic health.

“You can turn fat into muscle.”

Fat and muscle are two completely different types of tissue—one cannot transform into the other. Fat is stored energy, while muscle is active tissue. You can lose fat and gain muscle simultaneously through strength training and a proper diet, but they don’t “convert” into each other.

Science Says:
Research from the American Journal of Clinical Nutrition (2018) shows that resistance training combined with a high-protein diet helps preserve muscle while promoting fat loss, leading to a leaner appearance.

“Sweating means you’re burning more fat.”

Sweating is simply your body’s way of regulating temperature. Some people naturally sweat more than others, and external factors like humidity and temperature can make you sweat more during a workout. But sweating does not equate to fat loss—it’s just temporary water loss.

Science Says:
A 2010 study in Experimental Physiology confirmed that sweat rate is influenced more by genetics and climate than by calorie burn or fat loss. While a tough workout may cause sweating, actual fat loss is determined by caloric expenditure.

“The more you work out, the better.”

It’s tempting to think that more gym time equals faster results, but overtraining can stall progress, increase injury risk, and lead to burnout. Your muscles grow and recover during rest, not during constant exercise.

Science Says:
A study from the Journal of Sports Sciences (2016) found that excessive training without proper rest leads to elevated cortisol (a stress hormone), reduced performance, and higher injury rates. Training smarter—not just harder—yields better results.

“You need hours of cardio to lose weight.”

While cardio is beneficial for heart health, weight loss primarily comes down to calories in vs. calories out. Strength training and high-intensity interval training (HIIT) can be more effective for fat loss than long cardio sessions.

Science Says:
A meta-analysis in the British Journal of Sports Medicine (2019) concluded that HIIT burns 28.5% more fat than steady-state cardio in the same amount of time due to the afterburn effect (excess post-exercise oxygen consumption, or EPOC).

“Drinking coffee dehydrates you.”

Many people believe that because coffee is a diuretic, it causes dehydration. While caffeine can have a mild diuretic effect, moderate coffee consumption does not lead to dehydration. In fact, coffee contributes to daily fluid intake.

Science Says:
A study in PLOS One (2014) found that moderate coffee consumption hydrates the body similarly to water. The diuretic effect is only significant when caffeine is consumed in very high doses (above 500 mg/day). So, your morning coffee isn’t drying you out—it’s actually helping you stay hydrated!

“Doing ab exercises will give you a six-pack.”

Many people believe that crunches and sit-ups will magically reveal abs, but you can’t spot-reduce fat. Visible abs come from lowering overall body fat percentage through a combination of diet, strength training, and cardio.

Science Says:
A study in the Journal of Strength and Conditioning Research (2011) found that targeted abdominal exercises alone do not reduce belly fat—a comprehensive approach including diet and full-body training is required.

“If you don’t feel sore, you didn’t work out hard enough.”

Muscle soreness (DOMS) occurs when muscles experience microscopic tears, but it’s not the only sign of a good workout. Strength and endurance improvements don’t require constant soreness.

Science Says:
Research published in The Journal of Applied Physiology (2013) found that muscle soreness is not a reliable measure of workout effectiveness—progressive overload and consistency matter more.

Final Thoughts

Just like we outgrew childhood myths, it’s time to leave fitness myths behind too. The key to real progress is knowledge, balance, and consistency. So next time you hear someone say lifting weights makes you bulky, sweating equals fat loss, or coffee dehydrates you, you’ll know better—because science has your back.

What’s a fitness myth you used to believe? Drop it in the comments!