Nutrition Myths Debunked: What Is Actually True?

Why Nutrition Myths Are So Persistent

Nutrition is a topic where almost everyone has an opinion. Social media, advertising, and well-meaning advice ensure that half-truths spread and become perceived as established knowledge. The problem is that many of these beliefs are based on outdated studies, isolated cases, or plain marketing interests. The result is confusion. People who want to eat healthily often no longer know what is true and what is not.

Scientific evidence helps separate fact from fiction. In the following sections, eight common nutrition myths are examined based on current research.

The Myths in Detail

Myth 1: Detox Diets Cleanse the Body

The idea sounds logical: juice cleanses, teas, or special supplements are supposed to flush toxins from the body. The reality is quite different. The human body has a highly efficient detoxification system. The liver, kidneys, lungs, skin, and intestines work around the clock to break down and excrete metabolic byproducts and harmful substances.

Klein and Kiat (2015) analysed the available evidence on detox diets and reached a clear conclusion: there are no robust clinical studies that support the effectiveness of detox diets. No commercial detox product has been able to demonstrate which toxins it removes or through which mechanism it works.

Verdict: The body detoxifies itself. A balanced diet with adequate water, fibre, and micronutrients supports the natural detoxification organs most effectively. Expensive detox products are unnecessary.

Myth 2: Eating Late at Night Causes Weight Gain

This myth has persisted for decades. The logic behind it: because metabolism slows down at night, calories consumed in the evening are more likely to be stored as fat. Research contradicts this simplified view.

Total energy balance is what matters for body weight. Anyone who consumes more calories than they expend over the course of a day will gain weight. The timing of food intake plays a secondary role. A study by Sofer et al. (2011) even showed that participants who ate carbohydrates primarily in the evening had better satiety and more favourable hormone profiles than the control group.

However, there is an indirect connection: people who eat late at night tend to reach for calorie-dense snacks more frequently and eat in a less controlled manner. The problem is not the time of day but the behaviour.

Verdict: Eating in the evening does not inherently cause weight gain. The total daily calorie balance is the decisive factor for changes in body weight.

Myth 3: Gluten-Free Is Generally Healthier

Gluten-free products have been booming for years. Many people avoid gluten because they believe it is generally harmful or causes weight gain. For individuals with coeliac disease (approximately 1% of the population) or a diagnosed gluten sensitivity, a gluten-free diet is medically necessary. For everyone else, there is no proven health benefit.

In fact, the opposite may be true: gluten-free substitutes are often less nutritious than their wholegrain counterparts. They contain less fibre, fewer B vitamins, and more sugar and fat to compensate for taste and texture. Gaesser and Angadi (2012) warned in a review that unnecessary gluten avoidance can actually reduce overall dietary quality.

Verdict: Without a medical indication, a gluten-free diet offers no advantages. Wholegrain products containing gluten provide valuable fibre and micronutrients.

Myth 4: Superfoods Are Essential

Acai berries, chia seeds, goji berries, spirulina. New foods are regularly marketed as “superfoods” that are supposedly extraordinarily healthy. However, “superfood” is not a scientific term. It was coined by the food industry, and in the EU, it has been prohibited as an advertising claim without approved health claims since 2007.

No single food is indispensable or can compensate for an otherwise unbalanced diet. The European Food Safety Authority (EFSA) has not approved health claims for most foods marketed as superfoods. This does not mean that chia seeds or goji berries are bad. They are good foods with interesting nutrient profiles. But local alternatives such as flaxseeds, blueberries, or kale provide comparable nutrients at a fraction of the price.

Verdict: “Superfoods” are marketing terms. A varied diet with diverse fruits and vegetables is more effective than fixating on individual exotic foods.

Myth 5: High Protein Intake Damages the Kidneys

This myth originally comes from nephrology, where patients with existing kidney disease are indeed advised to eat a reduced-protein diet. However, extrapolating this to healthy individuals is not correct.

Antonio et al. (2016) examined the effects of a high-protein diet (2.2 g per kg of body weight) over one year in trained individuals. The result: neither kidney function nor blood lipid levels nor liver values deteriorated. A meta-analysis by Devries et al. (2018) also confirmed that protein intakes up to 2.2 g/kg do not impair kidney function in healthy adults.

An important note: for people with pre-existing kidney conditions, medical consultation is essential. The evidence applies exclusively to healthy individuals with normal kidney function.

Verdict: In healthy people, there is no evidence that a high-protein diet of up to 2.2 g/kg body weight damages the kidneys.

Myth 6: Breakfast Is the Most Important Meal of the Day

This phrase has been repeated for decades. In reality, the evidence is considerably more nuanced than the saying suggests. Early observational studies showed a correlation between skipping breakfast and higher body weight. However, these studies did not allow causal conclusions, as breakfast skippers often had generally less healthy lifestyle habits.

Randomised controlled trials paint a different picture. Sievert et al. (2019) analysed 13 studies in a meta-analysis and found no evidence that skipping breakfast leads to weight gain. Participants who skipped breakfast consumed fewer total calories over the course of the day.

At the same time, there is good evidence for the benefits of intermittent fasting, where breakfast is deliberately skipped. The research shows that there are valid arguments for both regular breakfast eating and skipping it.

Verdict: Whether or not to eat breakfast is an individual decision. Both approaches can be part of a healthy diet. What matters is the quality of the overall diet, not any single meal.

Myth 7: Organic Food Is Always More Nutritious

The assumption that organic foods automatically contain more vitamins and minerals is widespread. The evidence on this topic is surprisingly clear.

Baranski et al. (2014) published the largest meta-analysis to date on this subject, encompassing 343 studies. The findings were nuanced: organic products did indeed contain higher concentrations of antioxidants (18-69% more polyphenols) and significantly fewer pesticide residues. However, for classic nutrients such as vitamins, minerals, and macronutrients, the differences were small and inconsistent.

This means that the main advantage of organic products lies in reduced pesticide exposure and higher polyphenol content. Anyone who believes that an organic apple contains fundamentally more vitamin C than a conventional apple is mistaken. The differences in classic micronutrients are marginal.

Verdict: Organic products offer advantages regarding pesticide residues and polyphenol content. A significant nutritional advantage in terms of vitamins and minerals has not been demonstrated.

How to Read Nutrition Studies Critically

Correlation Is Not Causation

Many nutrition myths arise because observational studies are misinterpreted. Just because two things occur together does not mean that one causes the other. An example: studies show that breakfast skippers are more frequently overweight. The conclusion “skipping breakfast causes weight gain” is, however, incorrect. It may be that people who skip breakfast lead generally less health-conscious lifestyles.

Understanding Study Types

Not all studies carry the same weight of evidence. Randomised controlled trials (RCTs) provide the strongest evidence. Observational studies can identify associations but cannot prove causation. Case reports and animal studies cannot be directly applied to humans.

Consider Funding and Conflicts of Interest

Who funded a study does not automatically influence its outcome. However, industry-funded studies statistically show favourable results for the product under investigation more often. Transparency regarding conflicts of interest is a hallmark of good research.

Conclusion

Nutrition myths arise because complex science is reduced to simple messages. Reality is almost always more nuanced than a headline. Those who adhere to scientifically grounded principles can quickly debunk most myths: a balanced, varied diet rich in vegetables, fruits, whole grains, and quality protein sources. No detox tea, no superfood, and no miracle diet can replace this fundamental principle.

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Sources:

• Klein AV, Kiat H (2015). Detox diets for toxin elimination and weight management: a critical review of the evidence. Journal of Human Nutrition and Dietetics, 28(6), 675-686.
• Sofer S et al. (2011). Greater weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner. Obesity, 19(10), 2006-2014.
• Gaesser GA, Angadi SS (2012). Gluten-free diet: imprudent dietary advice for the general population? Journal of the Academy of Nutrition and Dietetics, 112(9), 1330-1333.
• Antonio J et al. (2016). A high protein diet has no harmful effects: a one-year crossover study in resistance-trained males. Journal of Nutrition and Metabolism, 2016, 9104792.
• Devries MC et al. (2018). Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets. Journal of Nutrition, 148(11), 1760-1775.
• Sievert K et al. (2019). Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials. BMJ, 364, l42.
• Baranski M et al. (2014). Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses. British Journal of Nutrition, 112(5), 794-811.