The food myths we hear everywhere... and that science contradicts

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The field of nutrition is one of those where false beliefs persist the longest, sometimes decades after science has contradicted them. The reasons are multiple: the complexity of nutritional research, the speed of dissemination of information on the Internet, the economic interests that support certain messages, and the human tendency to simplify complex biological realities into easy-to-remember rules. This article offers a rigorous scientific fact-check of 10 of the most widespread food myths in France.

1. The great food myths debunked

Widespread myth	What science actually establishes
Eggs raise cholesterol and are bad for the heart	FALSE. A meta-analysis published in the BMJ (2020) covering 2 million people found no association between moderate egg consumption (up to one a day) and cardiovascular risk. Dietary cholesterol has minimal impact on blood cholesterol in most individuals. Saturated and trans fats have a far greater effect.
Eating fruit in the evening makes you gain weight	FALSE. Fruit in the evening has no specific effect on weight gain. Weight gain results from an overall calorie surplus, not from the time at which a healthy food is eaten. Fruit is low in calories and rich in fibre and water. A banana in the evening does not disrupt metabolism.
Fats make you fat, so they should be avoided	OVERSIMPLIFIED. Healthy fats (olive oil, avocado, nuts, oily fish) are essential and protective. It is trans fats and excess saturated fats, combined with refined sugars, that cause problems. A low-fat diet is no better than a balanced diet for long-term weight control.
Bread makes you fat	FALSE in the context of a balanced diet. Bread, especially wholegrain sourdough, is a source of complex carbohydrates, fibre and B vitamins. What causes weight gain is an overall calorie surplus, not one specific food.
Eating in the evening makes you gain weight	MYTH. Meal timing has little influence on weight gain if the overall calorie balance is even. What is risky in the evening is emotional snacking in front of the television, not the evening meal itself. Studies on intermittent fasting add nuance to this message without confirming it outright.
Cow's milk is essential for bone health	OVERSTATED. Calcium from milk is well absorbed, but other sources are just as effective. Asian populations, who consume few dairy products, do not have higher osteoporosis rates than Western populations. Vitamin D and physical activity matter as much as calcium for bone health.
The sugar in fruit (fructose) is as bad as added sugar	FALSE. Fructose in whole fruit comes with fibre, water and antioxidants that slow its absorption and offset its negative effects. It is free fructose (the glucose-fructose syrup in industrial products) that is problematic, not the natural fructose in whole fruit.
Organic food is always more nutritious than non-organic	NUANCED. Nutritional differences between organic and non-organic products are modest according to the available meta-analyses. The main advantage of organic is reduced exposure to synthetic pesticides. Choosing organic for the most heavily treated produce (apples, strawberries, grapes) makes sense; for others the gap is minimal.
Cooking destroys all the vitamins in vegetables	EXAGGERATED. Cooking does destroy some heat-sensitive vitamins (vitamin C, folates) but it can increase the bioavailability of other nutrients (lycopene in tomatoes, beta-carotene in carrots). Steaming and short cooking preserve vitamins better than prolonged boiling.
Protein powders are necessary to build muscle	UNNECESSARY, with rare exceptions. A diet rich in natural protein (meat, fish, eggs, legumes, dairy) covers the needs of the vast majority of athletes. Protein powders are a practical convenience, not a necessity, even for demanding performance goals.

## 2. Why do these myths persist despite science?

Understanding the mechanisms behind the persistence of food myths allows you to be more resistant to them:

• ●Poor quality studies circulate as much as good ones: a study on 20 participants over 2 weeks does not have the same value as a meta-analysis of 100 studies on 500,000 people. However, the media often treat both with the same enthusiasm.

• ●Economic interests support certain messages: the food industry finances targeted studies and uses simplified messages to promote its products. The message 'fat makes you fat' was amplified by the diet industry, which had a direct economic interest in it.

• ●Narrative coherence is more attractive than nuance: eating eggs increases cholesterol is a simple and logical story. The metabolic reality is much more complex. Our brain prefers simplicity over nuance.

• ●Confirmation of an existing belief: we retain information that confirms what we already believe. If I believe that bread makes you gain weight and I read an article that confirms it, I share it. If I read the rebuttal, I'm more skeptical.

3. How to evaluate nutritional information

Some questions to ask myself when faced with a new nutritional statement:

• ●Is this a human study (more reliable) or an animal/laboratory study (less directly applicable)?

• ●How many people were included and for what duration? Large prospective studies over long periods are more reliable.

• ●Who financed this study? Funding bias exists in nutritional research.

• ●Is it an association (correlation) or a proven causal relationship? Correlation does not prove causation.

• ●Were the results confirmed by a meta-analysis or a systematic review of several independent studies?

• ●Do other nutrition experts agree on this conclusion?