Food myths have a long life. They spread through decades of magazine covers, government nutrition charts, and well-meaning family advice, and by the time science catches up, entire generations have already reorganized their diets around ideas that simply aren’t true. Food myths are beliefs, meaning nutritional concepts poorly justified or even contradicting existing scientific evidence, that are taken as the truth by individuals. Many existing myths are born from misinformation, and it is this lack of trustworthy knowledge about nutrition that results, most of the time, in conditions such as metabolic syndrome, hypertension, diabetes, and cardiovascular diseases. Here are four of the most persistent the science finally caught up.
1. Eating Fat Makes You Fat
The low-fat craze of the 1980s and 1990s was built on a simple but misguided assumption: fat has more calories per gram than protein or carbs, so eating less fat must lead to weight loss and better health. Fat-free yogurts, snacks, and processed foods filled supermarket aisles, often laden with sugar and refined starches to make up for lost flavor. This sweeping message was reinforced by the 1992 food pyramid, which placed fats at the very top as something to be used “sparingly,” and the low-fat era was underway on a massive, cultural scale.
Fat does not make you fat. We gain weight when we eat in excess of our needs, whether the excess comes from protein, carbohydrates, or fats. Research shows that people who eat a moderate or high fat diet lose just as much weight, or more, than people who eat a low-fat diet. Dietary fat doesn’t automatically convert to body fat. In fact, we now know that unsaturated fats, such as those from olive oil, nuts, seeds, and fatty fish, support heart health, hormonal function, and satiety. The landmark PREDIMED trial, published in the New England Journal of Medicine in 2018, showed that a Mediterranean diet rich in healthy fats reduced cardiovascular events more than a low-fat diet. Fat got a bad rap in the 1990s, when low-fat diets were all the rage, and many Americans are still confused about the role of fat in a healthy diet. We now know that all fats aren’t created equal.
2. Carbohydrates Are the Enemy of Weight Loss
Following the backlash against low-fat diets, a new scapegoat emerged: carbohydrates. The rise of Atkins, keto, and other low-carb regimens promoted the idea that all carbs, regardless of source, spike insulin, promote fat storage, and lead to metabolic dysfunction. The word “carb” itself became shorthand for “unhealthy.” This view conveniently ignored the massive nutritional difference between a handful of refined sugar and a bowl of whole-grain oats, treating all carbohydrates as a single threat.
A 2024 meta-analysis confirmed that when protein and calories are equated, low-carb diets result in statistically similar fat loss to high-carb diets. Carbs don’t automatically make you fat – overall calories, portion size, and carb quality matter far more than simply “low-carb vs high-carb.” Glucose is the preferred fuel for your brain and many tissues, so extreme carb restriction can leave you tired, foggy, and craving sugar. Large cohort studies like the Global Burden of Disease project, published in The Lancet in 2019, have consistently shown that diets rich in fiber-filled, minimally processed carbohydrates are associated with lower risk of disease and longer life. Cutting out carbs can mean missing out on essential nutrients like B vitamins, calcium, and dietary fiber.
3. Eggs Raise Your Cholesterol and Cause Heart Disease
For many years, eggs were unfairly blamed for high cholesterol and heart disease. The theory was that because eggs contain dietary cholesterol, they must be a major contributor to high blood pressure, high cholesterol, and cardiovascular disease. For years, experts assumed cholesterol-rich foods like eggs played a direct role in raising LDL cholesterol, often called “bad cholesterol,” and this assumption led to dietary guidelines that limited egg consumption. Millions of people dutifully switched to egg-white-only omelets and avoided yolks for decades, convinced they were protecting their hearts.
In 2025, a randomized, cross-over study published in The American Journal of Clinical Nutrition confirmed that consuming two eggs daily as part of a diet low in saturated fat actually led to reductions in LDL cholesterol after five weeks. Researchers separated the effects of cholesterol and saturated fat, finding that high dietary cholesterol from eggs, when eaten as part of a low saturated fat diet, does not raise bad cholesterol levels. Instead, it was the saturated fat that was the real driver of cholesterol elevation. Eggs and their yolks are packed with nutrients, including protein, calcium, phosphorus, potassium, selenium, folate, choline, vitamins A, D, E, and K, amino acids, omega-3 fatty acids, and lutein and zeaxanthin.
4. Low-Fat Products Are Healthier Than Their Full-Fat Counterparts
Products with the nutrition claims “low in fat” or “fat-free” may look healthy at first glance, but it may not necessarily be the case. The food industry enthusiastically embraced this myth, flooding shelves with low-fat versions of nearly every imaginable product, from cookies and cakes to dressings and dairy. In the 1990s, fat was removed from yogurts and cookies, but it was replaced with massive amounts of sugar to make the product palatable. Shoppers felt virtuous reaching for these items, without realizing the swap they were making.
Low-fat chips are lower in fat, but also higher in carbohydrates and sugar. “Sometimes we tend to eat more of low-fat foods thinking that they’re guilt free and we end up eating more calories than we wanted from the low-fat foods because they’re also not as satisfying and not as satiating.” Newer research shows starchy and sugary foods tend to contribute to visceral fat, which has been linked to heart disease and other conditions, while fatty foods tend to contribute to subcutaneous fat, which is less harmful. For overall health and weight loss, experts recommend choosing nutrient-dense whole foods over processed foods with added sugar and refined carbohydrates. As one dietitian put it: “Fat is not the enemy. What’s more important than the amount of fat we consume is the type of fat we consume.”
