9 Food Myths Debunked

There are nutrition myths that are surprisingly persistent. Some have actually been around for decades, while others have only become supposed truths through social media, influencers, or clever marketing. They all have one thing in common: They sound logical, are repeated countless times, and therefore seem credible.

But nutritional science thrives on new findings. With every major study, our understanding of how nutrition actually affects the body grows. Time and again, it becomes clear that some recommendations were too sweeping, others are based on misunderstandings, and some myths gained traction primarily through clever marketing. So it’s time to subject nine widespread health myths to a scientific fact-check.

Myth 1: Organic foods generally contain more vitamins

For many people, organic foods are automatically associated with a healthier diet. This is often based on the assumption that organically grown fruits and vegetables must necessarily contain significantly more vitamins and minerals than conventionally produced products. However, the evidence from studies is not that clear-cut.

While some studies¹ show slight differences in certain phytochemicals or antioxidants, the differences in classic vitamins and minerals are usually minor and hardly relevant to health. Factors such as variety, ripeness, storage, and transport time are far more decisive for nutrient content.

This by no means implies that organic products have no benefits. Organic farming can promote biodiversity, reduce the use of synthetic pesticides, and meet higher standards for animal welfare. Those who buy organic products therefore often do so for environmental or ethical reasons—not necessarily because of a significantly higher vitamin content.

Myth 2: Detox programs cleanse the body

Hardly any term sells better than “detox.” Juices, teas, powders, and fasting programs promise to cleanse the body of harmful substances and provide new energy.

Yet our bodies already have a highly developed detoxification system. The liver, kidneys, intestines, skin, and lungs work around the clock to eliminate metabolic waste and toxins. As long as these organs are functioning properly, they don’t need any additional detox products.

Many people do indeed feel lighter or more energetic during a detox regimen. However, this is usually because they are simultaneously cutting out alcohol, fast food, sweets, or highly processed foods and eating more mindfully overall. This positive effect can be achieved even without detox products. A balanced diet provides the body with the nutrients it needs for its normal metabolic processes. These include, for example, protein and various vitamins and trace elements that are involved in numerous enzymatic reactions in the body.

Myth 3: If you eat a healthy diet, you don’t need dietary supplements

At first glance, this statement sounds reasonable. In fact, a balanced diet can meet the body’s needs for most vitamins and trace minerals. The reality, however, is much more complex.

Depending on life stage, age, medical conditions, or individual circumstances, even people with an exemplary diet can develop deficiencies. Vitamin D is the best-known example of this, as the body’s own production is often insufficient in our latitudes, especially in winter. Iodine, iron, folic acid, and vitamin B12 can also frequently become critical, depending on the situation.²

That is why the principle that dietary supplements are generally unnecessary no longer applies today. What matters much more is how varied and fresh your diet is, how well your gut can absorb nutrients, and whether you have an increased need for certain nutrients.

Myth 4: Eating after 6 p.m. makes you gain weight

This myth is persistent and has likely caused many people to go to bed hungry in the evening. But the truth is much more nuanced: It’s not the time of day alone that determines whether we gain weight, but rather our overall energy balance throughout the day.

The truth is: Our metabolism changes throughout the day. In the evening, insulin sensitivity is often slightly lower than in the morning, meaning the body responds to carbohydrates somewhat less efficiently and blood sugar levels may rise more sharply after a meal.³ Energy expenditure also generally decreases as we tend to be less active in the evening. These factors may explain why very late and large meals can be problematic for some people.

However, this leads to the false conclusion that eating after 6 p.m. generally causes weight gain. If you eat a balanced meal around 7 or 8 p.m. and do not exceed your total energy needs, you will not automatically gain weight as a result. What matters much more is what and how much you eat throughout the entire day.

Eating late becomes problematic especially when it occurs in addition to regular meals—for example, in the form of snacks, sweets, or large portions while watching TV. Furthermore, a very heavy meal shortly before bedtime can impair sleep quality.

Therefore, the better rule isn't “don't eat anything after 6 p.m.,” but rather: Eat mindfully in the evening, pay attention to portion sizes, and adjust your meal to fit your own daily rhythm.

Myth 5: Gluten Is Generally Unhealthy

Gluten has undergone a major image transformation in recent years: What used to be simply a natural component of bread and grains is now considered by many people to be something best avoided. Gluten-free products are often marketed as “healthy,” “light,” or “easier to digest”—but this isn’t true for everyone.

Gluten is a protein that occurs naturally in wheat, rye, and barley. For people with celiac disease, a wheat allergy, or a diagnosed gluten sensitivity, it can indeed trigger symptoms and make a gluten-free diet necessary.

For the vast majority of people, however, gluten is not a health issue. Studies show no benefits of a gluten-free diet for people without these conditions. On the contrary: those who avoid gluten-containing foods for no valid reason often eliminate important sources of fiber—such as whole-grain bread or whole grains—from their diet.

Furthermore, gluten-free processed foods are not automatically healthier. Many contain less fiber and, in some cases, more sugar, fat, or additives than comparable products containing gluten. What matters, therefore, is not whether a food is gluten-free—but whether it is nutritionally rich overall and sensibly incorporated into one’s diet.

Myth 6: Vitamin B12 deficiency affects only vegans

Vitamin B12 is often associated exclusively with a vegan diet. While it is true that vegans who do not take supplements are among the at-risk groups, they are by no means the only ones affected.

Many people who follow a mixed diet also eat significantly less meat and processed meats today than they did a few decades ago. While this is often a healthy choice, it can lead to a lower overall intake of vitamin B12—especially if dairy products and eggs are also rarely included in the diet. That’s why it’s important to keep an eye on your intake.

Furthermore, the body’s ability to absorb the vitamin often decreases with age. Chronic gastrointestinal diseases, certain medications such as proton pump inhibitors or metformin, and stomach surgery can also significantly impair vitamin B12 absorption.⁴ As a result, a vitamin B12 deficiency can occur in people who follow a mixed diet as well—often going unnoticed for many years.

Myth 7: More Protein Is Always Better

Protein has been experiencing a real boom in recent years. Whether it’s yogurt, pudding, bread, or even ice cream—hardly any food product is sold without the “High Protein” label these days. It’s easy to get the impression that as much protein as possible is automatically healthier and that the body can’t get enough of it.

In fact, protein is one of the most important nutrients of all. It provides the building blocks for muscles, enzymes, hormones, and the immune system. In addition, protein-rich meals are particularly filling because they promote the release of satiety hormones and ensure that blood sugar rises more slowly. That’s why protein-rich foods play an important role in weight management.

Added to this is an intriguing mechanism in our bodies: experts are discussing the so-called protein leverage hypothesis.⁵ It suggests that humans have a certain protein requirement and may continue to feel hungry until this need is met. If the diet contains too little protein, some people therefore end up consuming more calories overall in order to meet their protein needs. This could explain why low-protein, highly processed foods often aren’t as filling.

However, this does not mean that more protein is automatically better. Once an individual’s needs are met, additional protein generally does not provide any further health benefits. It does not automatically lead to more muscle mass, nor does it replace strength training or an overall healthy lifestyle.

Therefore, the key is not to replace every food item with a high-protein alternative, but to meet your personal needs in a sensible way—ideally through high-quality protein sources such as legumes, dairy products, fish, eggs, nuts, or lean meat, as part of an overall balanced diet.

Myth 8: Fiber Is Important Only for Digestion

For a long time, fiber had a rather uninspiring reputation. It was considered a home remedy for constipation and was recommended primarily to people who wanted to give their digestion a little boost. Today, scientists know that this view falls far short of the mark.

Dietary fiber is now one of the most thoroughly researched components of a healthy diet. It serves as food for the trillions of microorganisms in the gut. When fermented, it produces short-chain fatty acids such as butyrate, which strengthen the intestinal barrier, influence inflammatory processes, and can even affect metabolism and the immune system.⁶ No wonder, then, that the gut microbiome has become one of the most exciting areas of research in nutritional medicine in recent years.

But the positive effects don’t stop at the gut. High-fiber meals ensure that carbohydrates are absorbed more slowly and that blood sugar levels rise less sharply. At the same time, they promote the release of satiety hormones and help many people regulate their body weight more easily. Cholesterol levels can also improve, particularly through soluble fiber from oats, barley, or legumes.

A widely cited analysis in the medical journal The Lancet⁷ demonstrates just how significant this impact actually is: People with a high fiber intake had a significantly lower risk of cardiovascular disease, type 2 diabetes, and colorectal cancer, and had an overall lower mortality rate than those with a low-fiber diet.⁸ Even as little as 25 to 30 grams of fiber per day was associated with these health benefits.

Fiber is therefore far more than just a digestive aid; it is a true key to health—and ranks among the most underrated nutrients in our diet.

Myth 9: Plant-based milk alternatives are always healthier

Oat, soy, almond, and pea drinks have experienced a veritable boom in recent years. For many consumers, it’s therefore a given: Plant-based alternatives must automatically be the healthier choice than cow’s milk. However, it’s not that simple. This is because plant-based drinks vary considerably in their nutrient composition and the additives used, depending on the raw materials and recipe.

Soy drinks, for example, naturally provide a comparatively high amount of high-quality protein and come relatively close to cow’s milk in terms of protein content. Almond drinks, on the other hand, often contain only small amounts of protein. Oat drinks provide more carbohydrates and can contain varying amounts of sugar depending on the manufacturing process and recipe. Some products also contain added sugar, flavorings, stabilizers, or other additives used to enhance taste, texture, or shelf life. It’s therefore worth taking a look at the ingredient list.

There are also differences in the content of important micronutrients. Cow’s milk naturally provides calcium, vitamin B2, and vitamin B12, among other nutrients. Many plant-based beverages, on the other hand, contain these nutrients in comparable amounts only if they have been specifically fortified with them. Whether a plant-based beverage is a good alternative to cow’s milk therefore also depends on whether and how it has been fortified. With cow’s milk, on the other hand, the nutrient profile varies depending on the fat content.

Whether plant-based alternatives or cow’s milk from animal-welfare-friendly, organic farming is the better choice ultimately depends on individual preferences, health considerations, sustainability factors, and the specific product composition. It’s worth taking a look at the ingredient list.

Conclusion: Nutrition is rarely black and white

Perhaps this is the most important insight of modern nutritional science: Health can hardly be reduced to simple rules. There are few absolute truths, but many shades of gray.

It’s not a single “superfood” ingredient, the perfect mealtime, or the next miracle cure that determines our health—it’s the big picture. A varied diet, plenty of fruits and vegetables, whole grains, high-quality protein sources, sufficient fiber, and a lifestyle that includes exercise and adequate sleep have a much greater long-term impact than any short-term trend.

Those who take a critical look at nutrition and prioritize scientific evidence over myths usually make better decisions—and can enjoy their food with much greater peace of mind at the same time.