Food Myths You Still Believe: What Science Really Says

Discover the biggest food myths debunked by science. Does egg increase cholesterol? Does eating at night make you fat? Does banana cause constipation? Answers based on scientific evidence.

"Don't Eat Eggs Every Day, It Raises Cholesterol!"

"Don't Drink Water During Meals, It Hinders Digestion!"

"Carbs at Night Turn Straight Into Fat!"

How many times have you heard (or even repeated) phrases like these?

The truth is that nutrition is one of the areas most filled with myths and popular beliefs — many passed down from generation to generation, without any scientific basis.

And worse: while you follow these myths, you might be harming your health or, at the very least, complicating your life unnecessarily.

In this article, we'll debunk the 15 most popular food myths, showing what science really says about each one.

Brace yourself: some truths might surprise you (and even irritate your aunt at the next family lunch).

Why Do We Believe in Food Myths?

Before starting, it's worth understanding: why are these myths so persistent?

3 main reasons:

1. OUTDATED INFORMATION

Nutrition science evolves. What was true 40 years ago has been disproven by more recent research. But old information keeps circulating.

2. IMPROPER GENERALIZATION

An isolated study becomes a sensationalist headline. "Coffee causes cancer!" — ignoring that it was absurd doses in laboratory rats.

3. FAMILY TRADITION

"My grandmother always said that..." — and we repeat without questioning. Popular wisdom isn't always correct (with all due respect to grandmothers).

The antidote? Science. Peer-reviewed studies. Meta-analyses. Scientific consensus.

Let's get to the myths!

MYTH 1: "Eating Eggs Every Day Increases Cholesterol"

❌ THE MYTH

Eggs are rich in cholesterol (186mg per unit). Therefore, eating eggs increases blood cholesterol and causes heart disease.

✅ THE SCIENTIFIC TRUTH

The cholesterol you eat has LITTLE impact on blood cholesterol.

Your liver produces about 1,000mg of cholesterol per day. When you eat cholesterol-rich foods, the liver simply produces less to compensate.

Recent studies show:

• Consuming up to 3 eggs per day doesn't increase cardiovascular risk in healthy people (Study published in British Medical Journal, 2020)

• Eggs are one of the best sources of high biological value protein

• Rich in choline (important for brain), vitamin D, B12, selenium

WHAT REALLY INCREASES BAD CHOLESTEROL?

• Trans fats (industrial cookies, chips)

• Excess saturated fat (fatty meats, excessive whole dairy)

• Excess sugar and refined carbohydrates

• Sedentary lifestyle and smoking

CONCLUSION: Eggs are healthy. You can eat 1-2 per day without worry (unless you have genetic familial hypercholesterolemia — then yes, talk to your doctor).

MYTH 2: "Eating at Night Makes You Gain More Weight"

❌ THE MYTH

Calories consumed at night are stored as fat because you'll sleep and won't spend energy.

✅ THE SCIENTIFIC TRUTH

Your body burns calories 24 hours a day — including while sleeping.

During sleep, you spend energy to:

• Breathe

• Pump blood

• Regulate temperature

• Repair tissues

• Consolidate memory

Studies show:

• What matters is TOTAL daily calories, not timing (Research from Obesity Journal, 2019)

• People who eat at night don't gain more weight than people who eat early, if total calories are equal

• Skipping dinner can cause excessive hunger the next day and loss of eating control

WHY DOES THE MYTH PERSIST? Many people eat at night emotionally: day stress, watching TV, without paying attention to quantities. The problem isn't the timing — it's eating unconsciously.

CONCLUSION: Eat at night if you're hungry. What matters is the total caloric balance of the day, not the clock.

MYTH 3: "Detox Juice Eliminates Body Toxins"

❌ THE MYTH

Special green juices "cleanse" the body, eliminate accumulated toxins, and promote rapid weight loss.

✅ THE SCIENTIFIC TRUTH

You already have detox organs: liver and kidneys.

They do this 24/7, for free, without needing a $15 green juice.

There's no accumulated toxin that needs "cleansing":

• If your toxins aren't being eliminated, you're in kidney or liver failure — and need a hospital, not juice

• No food "cleanses" the body magically

• Detox juices don't accelerate elimination of anything

WHAT JUICES REALLY DO:

• Provide vitamins and minerals (which is good!)

• Hydrate (also good!)

• Are low in calories (if no added sugar)

• BUT: Lose fruit fibers (which is bad)

CONCLUSION: Green juices are nutritious, but don't detox. Your liver and kidneys already take care of that. Want to help them? Drink water, eat fiber, sleep well, and avoid excess alcohol.

MYTH 4: "Carbs at Night Turn Into Fat"

❌ THE MYTH

Carbohydrates consumed at night automatically transform into body fat because you won't spend them.

✅ THE SCIENTIFIC TRUTH

There's no magic time when carbs turn into fat.

The process is called lipogenesis (conversion of carbohydrate to fat), and it happens when:

• You consume MORE calories than you spend (regardless of time)

• Your glycogen stores (muscle and liver energy) are already full

Interesting studies:

• Athletes who consume most carbs at night don't gain more fat (Study published in British Journal of Nutrition, 2011)

• Carbs at night can even help sleep quality, as they increase serotonin

WHY DO PEOPLE BELIEVE THIS? Many people overdo dinner: giant pastas, breads, desserts — an obvious caloric excess. The problem isn't the carb, nor the time. It's the QUANTITY.

CONCLUSION: Carbs at night aren't villains. Caloric excess is. Plan your meals according to your lifestyle.

MYTH 5: "Bananas Cause Constipation"

❌ THE MYTH

Bananas, especially if "green" (firmer), constipate and should be avoided by those with sluggish bowels.

✅ THE SCIENTIFIC TRUTH

Depends on ripeness point:

GREEN BANANA (firmer):

• Rich in resistant starch (type of fiber)

• Can make bowels slower in some people

• Works as prebiotic (feeds good bacteria)

RIPE BANANA (with spots):

• Starch becomes sugar

• Easier to digest

• Rich in soluble fibers that help intestinal transit

• Source of potassium (relaxes intestinal muscles)

Studies show:

• Ripe banana doesn't cause constipation in most people

• Can even help with diarrhea cases (pectin regulates transit)

CONCLUSION: Ripe banana doesn't cause constipation. If you have sensitive bowels, avoid very green ones. Otherwise, eat without fear.

MYTH 6: "Milk Causes Mucus and Worsens Flu/Cold"

❌ THE MYTH

Milk increases mucus (phlegm) production and should be avoided when you have flu or cold.

✅ THE SCIENTIFIC TRUTH

There's no relationship between milk consumption and mucus production.

Scientific studies:

• Research published in American Review of Respiratory Disease (1990): No increase in mucus production in people who drank milk

• What happens: milk can make saliva temporarily thicker, giving a phlegm sensation — but it ISN'T phlegm

WHY DO PEOPLE FEEL THIS? Milk has creamy texture. Mixed with saliva, creates a "mucus" sensation in throat. It's sensory, not physiological.

EXCEPTION: If you have milk protein allergy or lactose intolerance, then milk does cause problems — but it's not mucus, it's allergic/digestive reactions.

CONCLUSION: Milk doesn't increase phlegm. If you don't have allergy or intolerance, you can consume normally, even when sick.

MYTH 7: "Fruit After Meals Ferments in Stomach"

❌ THE MYTH

Eating fruit as dessert makes it "ferment" in the stomach, causing bloating, gas, and hindering digestion.

✅ THE SCIENTIFIC TRUTH

There's no significant fermentation in the stomach.

Your stomach is acidic (pH between 1.5 and 3.5) — hostile environment for fermentation. Fermentation happens in the intestine, not stomach, and is a normal and healthy process.

What really happens:

• Your stomach mixes all foods (protein, carbohydrate, fat, fruit)

• Digestion begins and moves to intestine

• There's no magic "exit order" where fruit gets stuck waiting

WHY DO SOME PEOPLE FEEL DISCOMFORT?

• Eating too much in general (meal + dessert = excessive volume)

• Slow digestion of very fatty meals

• Individual sensitivity to fructose (fruit sugar)

CONCLUSION: Fruit doesn't ferment in stomach. You can eat as dessert without worry. If you feel discomfort, maybe the problem is total food quantity, not the fruit.

MYTH 8: "Cold Water Hinders Digestion"

❌ THE MYTH

Cold water "solidifies" food fats, making digestion difficult and causing health problems.

✅ THE SCIENTIFIC TRUTH

Your body maintains constant internal temperature (~98.6°F/37°C), regardless of what you drink's temperature.

When you drink cold water:

• It passes through mouth and esophagus

• Reaches stomach

• Is quickly warmed to body temperature

• Doesn't affect fat digestion

Studies show:

• No difference in digestion speed between cold, warm, or hot water

• Fat is digested by enzymes (lipases), not temperature

POSSIBLE DISCOMFORT: In people with irritable bowel syndrome or digestive sensitivity, very cold water CAN cause temporary discomfort — but doesn't harm digestion.

CONCLUSION: Cold water doesn't hinder digestion. Drink at whatever temperature you prefer.

MYTH 9: "Skipping Meals Slows Metabolism"

❌ THE MYTH

Going without eating for a few hours "turns off" your metabolism, making the body enter "economy mode" and store fat.

✅ THE SCIENTIFIC TRUTH

Your metabolism doesn't slow down significantly in short fasts (up to 48-72h).

What science says:

• Fasts of 16-24h can even temporarily INCREASE metabolism (noradrenaline release)

• "Economy mode" only happens in prolonged fasts (days) or very restrictive diets for weeks

• Intermittent fasting studies show no significant metabolic slowdown

WHEN METABOLISM REALLY SLOWS DOWN:

• Very low-calorie diets for weeks/months

• Loss of muscle mass

• Chronic nutritional deficiencies

THE PROBLEM WITH SKIPPING MEALS: It's not metabolism — it's uncontrolled hunger afterward, leading to excess in next meals.

CONCLUSION: Skipping a meal doesn't "turn off" your metabolism. But eating regularly can help control hunger and avoid excesses.

MYTH 10: "Negative Calorie Foods Exist"

❌ THE MYTH

Some foods (celery, cucumber, lettuce) spend more calories being digested than they provide, resulting in "negative calories."

✅ THE SCIENTIFIC TRUTH

Negative calorie foods don't exist.

The thermic effect of food (energy spent digesting them) represents at most 30% of food calories — never more than 100%.

Real examples:

CELERY:

• Provides: ~6 calories per stalk

• Spends on digestion: ~1-2 calories

• Balance: +4-5 calories (positive, not negative)

CUCUMBER:

• Provides: ~8 calories per 100g

• Spends on digestion: ~2 calories

• Balance: +6 calories

WHY DO THESE FOODS HELP WITH WEIGHT LOSS? Not because of "negative calories," but because:

• Very low in calories

• Rich in water and fiber (provide satiety)

• Replace more caloric foods

CONCLUSION: Negative calories are a myth. But low-calorie vegetables are great for satiety and weight control.

MYTH 11: "Gluten is Bad For Everyone"

❌ THE MYTH

Gluten is inflammatory, causes bloating, harms the intestine, and should be avoided by everyone.

✅ THE SCIENTIFIC TRUTH

Gluten is only harmful to those who have:

1. CELIAC DISEASE (1% of population)

• Severe autoimmune disease

• Gluten causes intestinal damage

• Must eliminate 100% of gluten

2. NON-CELIAC GLUTEN SENSITIVITY (6% of population)

• Digestive symptoms with gluten

• No intestinal damage

• Can reduce or avoid

3. WHEAT ALLERGY (rare)

• Allergic reaction to wheat protein

• Can be severe

FOR THE OTHER 93% OF POPULATION: Gluten causes no problem whatsoever. Foods with gluten (whole grain breads, oats, rye) are nutritious and healthy.

WHY DO SO MANY PEOPLE "FEEL BETTER" WITHOUT GLUTEN? Usually, when eliminating gluten, the person eliminates:

• White breads

• Industrial cookies

• Refined pastas

• Chips

In other words: cut ultra-processed foods, not gluten. Improvement comes from eating better in general.

CONCLUSION: If you don't have celiac disease or proven sensitivity, you don't need to avoid gluten. Whole grains with gluten are healthy.

MYTH 12: "Sweeteners Are Always Better Than Sugar"

❌ THE MYTH

Artificial sweeteners have no calories, so they're always the healthier choice.

✅ THE SCIENTIFIC TRUTH

The situation is more complex:

GOOD SIDE OF SWEETENERS:

• Don't raise blood sugar (good for diabetics)

• Don't cause cavities

• Can help with caloric reduction

PROBLEMATIC SIDE:

• Some studies suggest artificial sweeteners may alter gut microbiota

• Can maintain addiction to sweet taste

• Don't help reeducate palate

• Still debates about long-term safety of some types

WHO GUIDANCE (2023): Non-caloric sweeteners aren't recommended as long-term strategy for weight control.

BEST SWEETENERS (if using):

• Stevia (natural)

• Erythritol (natural)

• Sucralose (in moderation)

MOST CONTROVERSIAL:

• Aspartame (reclassified as "possibly carcinogenic" by WHO in 2023)

• Saccharin

• Cyclamate

CONCLUSION: Sweetener isn't a villain, but also isn't a magic solution. Use in moderation and prefer natural ones. Even better: gradually reduce sweetness in diet.

MYTH 13: "Eating Every 3 Hours Speeds Up Metabolism"

❌ THE MYTH

Making small meals every 3 hours keeps metabolism "accelerated" and helps with weight loss.

✅ THE SCIENTIFIC TRUTH

Meal frequency doesn't alter metabolism significantly.

Studies show:

• No difference in energy expenditure between eating 3 or 6 meals a day, if total calories are equal

• Thermic effect of food is proportional to calories consumed, regardless of how many times you eat

ADVANTAGES OF EATING MORE OFTEN:

• Can help control hunger in some people

• Prevents "hunger attacks" and excess

ADVANTAGES OF EATING LESS OFTEN:

• Practicality (less preparation)

• Some people feel better

• Intermittent fasting may have metabolic benefits

CONCLUSION: There's no universal ideal frequency. Eat as many times a day as you feel better and can control total calories. What matters is the day's energy balance, not number of meals.

MYTH 14: "Fresh Juice Is As Healthy As Whole Fruit"

❌ THE MYTH

Freshly squeezed orange juice is equivalent to eating whole oranges.

✅ THE SCIENTIFIC TRUTH

Juice removes fruit fiber, completely changing metabolic impact.

COMPARISON:

1 WHOLE ORANGE:

• Fiber: 3g

• Sugar: 12g

• Chewing: signals satiety

• Absorption: slow and gradual

• Glycemic impact: moderate

JUICE FROM 3 ORANGES (1 glass):

• Fiber: 0.5g (almost nothing)

• Sugar: 36g (3x more!)

• Chewing: zero

• Absorption: fast

• Glycemic impact: high (insulin spike)

STUDIES SHOW:

• Regular fruit juice consumption is associated with higher risk of type 2 diabetes

• Whole fruits are associated with LOWER risk

CONCLUSION: Whole fruit >>> fresh juice. If drinking juice, prefer with pulp and limit to 1 small glass occasionally. Even better: eat the fruit.

MYTH 15: "Margarine Is Healthier Than Butter"

❌ THE MYTH

Margarine is plant-based, so it's healthier than butter (animal-based).

✅ THE SCIENTIFIC TRUTH

Not always plant-based = healthier.

BUTTER:

• Saturated fat (yes, but natural)

• Vitamins A, D, E, K

• No additives (if pure)

• ~717 calories per 100g

MARGARINE:

• May contain trans fats (terrible for health)

• Hydrogenated vegetable oil (chemical processing)

• Additives, emulsifiers, flavorings

• ~720 calories per 100g

RECENT STUDIES:

• Butter's saturated fat isn't as villainous as once thought

• Margarine's trans fats ARE proven bad

• Butter in moderation is acceptable in balanced diet

IMPORTANT: Not all margarine has trans fats. Read the label! Prefer those that say "0g trans fat."

BEST OPTION: Butter in moderation or trans-free margarines. Even better: extra virgin olive oil.

CONCLUSION: Butter isn't a villain. Margarine isn't a hero. Use either in moderation, preferring trans-free versions.

Summary: Truth Table

MYTH VERDICT WHAT TO DO Eggs increase cholesterol ❌ FALSE Can eat 1-2 per day Eating at night makes you gain more weight ❌ FALSE Total daily matters Detox juice eliminates toxins ❌ FALSE Your liver already does this Carbs at night turn to fat ❌ FALSE Caloric excess causes weight gain Bananas cause constipation ⚠️ DEPENDS Green can, ripe doesn't Milk causes mucus ❌ FALSE Can consume normally Fruit ferments after meals ❌ FALSE Eat whenever you want Cold water hinders digestion ❌ FALSE Drink at preferred temperature Skipping meals slows metabolism ❌ FALSE Short fasts don't affect Negative calorie foods ❌ FALSE Don't exist Gluten is bad for everyone ❌ FALSE Only for celiacs/sensitives Sweetener always better than sugar ⚠️ COMPLEX Use in moderation Eating every 3h speeds metabolism ❌ FALSE Frequency doesn't matter much Juice = whole fruit ❌ FALSE Fruit >>> juice Margarine better than butter ❌ FALSE Both in moderation

How Not to Fall for New Myths

5 QUESTIONS TO EVALUATE NUTRITIONAL INFORMATION:

1. IS THE SOURCE RELIABLE? ✅ Scientific studies, nutritionists, doctors ❌ "Experts" without training, influencers selling products

2. IS IT TOO GOOD TO BE TRUE? "Lose 22 lbs in 1 week" = lie "This food cures cancer" = lie Miraculous promises are always suspicious

3. IS THERE CONFLICT OF INTEREST? Who's spreading it sells the product? Is there company sponsorship?

4. DOES THE CLAIM HAVE QUALITY STUDIES? One isolated study ≠ scientific consensus Human studies > rat studies Meta-analyses > individual studies

5. DOES IT MAKE BIOLOGICAL SENSE? "Lemon water on empty stomach melts fat" — how?? If it sounds like magic, it's probably a lie

Conclusion: Think Critically, Live Better

Nutrition doesn't need to be complicated.

When in doubt, go back to basics:

• Eat real food

• Avoid ultra-processed

• Vary foods

• Listen to your body

• Don't fall into extremism

And especially: question.

That nutritional tip your aunt shared on WhatsApp? Is it true?

That "revolutionary discovery" you saw on Instagram? Does it have real studies?

You don't need to believe in myths to be healthy. You need quality information.

And now you have it.

Which of these myths surprised you most? Share with someone who still believes them!

📚 Scientific References:

• British Medical Journal - Studies on eggs and cholesterol (2020)

• Obesity Journal - Research on meal timing (2019)

• British Journal of Nutrition - Nighttime carbohydrates and body composition (2011)

• American Review of Respiratory Disease - Milk and mucus production (1990)

• WHO - Guidelines on non-caloric sweeteners (2023)

• American Society for Nutrition

• Academy of Nutrition and Dietetics

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Tags: nutrition myths, food myths debunked, nutrition facts, science-based nutrition, healthy eating myths, cholesterol and eggs, eating at night, detox myths, carbs at night, gluten sensitivity, intermittent fasting, metabolism myths, food science, evidence-based nutrition, nutritional misinformation

Disclaimer: This article is for informational purposes. For personalized nutrition advice, especially if you have specific health conditions, consult a registered dietitian or healthcare provider.