Food Myths vs Facts: Debunking Common Misconceptions in Nutrition

Myths about foods have a great impact on the health of the individual, public perception, and people's dietary behavior. People are misled to make wrong choices, such as total abstinence from fats or carbs; this leads to deficiencies in nutrition and cuts down on diets that are actually balanced. On a larger scale, popular myths force diet fads that are not needed and raise the demand for specialty foods, generally gluten-free or detox products, which often come at an exorbitant price without health benefits that are assured. Myths also create fear towards food and an unhealthy relationship with it, such as orthorexia, an unhealthy focus on eating in a healthy way. These are usually misconceptions that forbid sustainable and culturally diverse diets, which can promote non-useful, restrictive eating in the long run. It is thus important to emphasize these points for the readers by using scientific information to foster the balance and variety in eating that will encourage healthier and more sustainable dietary choices and a healthy relationship with food. It is important to debunk some of the most common food myths, providing evidence-based facts to help individuals make informed dietary choices.

Myth 1: Carbohydrates are bad for you

Probably, the most widespread myth here is that one should not eat carbohydrates at all because they substantially harm one's health. Yet, carbohydrates represent one of the macronutrients which substantially provide energy to the organism, particularly for the activity of the brain and muscles. The misunderstanding occurs because of a lack of differentiation between refined and complex carbs. Refined carbohydrates, like those from white bread, pastries, and sweet snacks, are of low nutritional value and promote weight gain and metabolic problems. By contrast, complex carbohydrates-whole grains, legumes, vegetables, and fruits-are packed with fiber, vitamins, and minerals that aid digestion, modulate blood sugar, and ensure a proper energy supply.

A balanced intake of unrefined carbohydrates fuels physical and mental performance because of their graduated release of glucose-the substance that muscles need to power and sustain the activity of the brain. Since unrefined carbohydrates are digested slowly, digestion serves to regulate blood sugar levels and supply the body with a continual energy source. Such an energy resource can support long-lasting effort and endurance in heavy physical work, while also maintaining the possibility of sustained mental focus, sharpness, and memory. Carbohydrates such as those found in fruits, vegetables, beans, and whole grains supply fiber and an array of nutrients that help to support optimal health and help to protect against the onset of chronic diseases like heart disease and diabetes. While low-carb diets tend to focus on the reduction of bread and pasta, for example, as one avenue toward weight loss, it is generally the excessive intake of refined, sugar-laden carbohydrates that is the more prominent factor leading to weight gain and metabolic disorders, rather than the simple carbohydrate per se. Thus, the emphasis needs to be on moderation in consumption and the choice of fibre-rich, minimally processed sources of carbohydrates to support body functions and ensure good health, rather than their complete elimination.

Myth 2: Eating fat makes you fat

For years, fat has been demonized, and low-fat diets have been recommended as one way to protect against weight gain and disease. This belief, teamed with consumer interest, spurred the growth of the low-fat and fat-free food industries in which added sugars or sodium are usually substituted for fat to maintain flavor. Thus, what the public got back was often just as calorie-laden but with more refined carbohydrates replacing the fat. This shift inadvertently led to the rise in obesity and metabolic disorders.

Let me bring out that not all fats are bad; some fatty acids are absolutely necessary in human physiology and thus ought to be part of a good diet. Healthy fats, particularly unsaturated fats from sources like olive oil, avocados, nuts, and fatty fish, support heart health, regulate cholesterol levels, and benefit cognitive functions.

Within Sri Lanka, various species of oily fish found include Yellowfin Tuna (Thunnus albacares), Sardines (Sardinella spp.), Indian Mackerel (Rastrelliger kanagurta), Anchovies (family Engraulidae), and Cuttlefish (Sepia spp.), which are all rich in omega-3 fatty acids necessary for cardiovascular health and cognitive health. These species occur in all marine ecosystems around Sri Lanka and form part of a health-promoting diet because of their nutritional value. Adding these fish to the diet can be very healthy for an individual and, particularly, heart health.

A balanced approach to fat intake indicates that daily calorie amount should derive 25-30% from fat. It is essential to emphasize the consumption of unsaturated fats while regulating the intake of saturated and trans fats. Foods included in lean meat, low-fat dairy products, and most especially fatty fish, and limit processed foods and fast foods for maintaining heart-healthy and other areas of general health.

Healthy fats are an absolute necessity to the diet since they act as nutrient carriers, sources of energy, and nutrient absorbers, in addition to protecting against chronic disease. Monounsaturated and polyunsaturated fats have a positive impact on one's blood lipid profiles in that they lower LDL cholesterol and, hence, the risk of heart disease. On the other hand, saturated and trans fats raise LDL cholesterol and, subsequently, increase the risks of heart attacks and strokes and are typically found in red meat, butter, and most processed foods. Trans fats are particularly harmful because they not only raise LDL cholesterol but also lower HDL cholesterol, which has a protective effect on heart health.

Studies have shown that weight management diets with an adequate amount of healthy fats can be at least as, if not more, effective as compared to low-fat diets. Low-carb diets with high fat levels have been often reported to result in the most significant weight loss, better triglycerides, and an improvement in blood sugar levels when compared with a typical low-fat, high-carbohydrate diet. Rather than trimming fat altogether, the intake of fat needs attention by replacing less healthy ones with healthier ones. 

Myth 3: Cholesterol is bad

Cholesterol often carries a negative connotation, but it is actually a very important molecule for a lot of physiological functions. Having in mind the difference between cholesterol in its natural state and cholesterol in its oxidized and glycated states could help to give a better picture about the effect of cholesterol on health. Naturally occurring cholesterol has a very important function in hormone synthesis, in vitamin D synthesis, and in synthesis of bile acids, all facilitating fat digestion and absorption. It also constitutes an important component of cell membranes and maintains their fluidity and functionality.

Cholesterol circulates in the bloodstream, mainly as Low-Density Lipoprotein and High-Density Lipoprotein. More commonly referred to as "bad" cholesterol, LDL carries a greater amount of cholesterol and, in excess, deposits into the wall of the arteries to build up as plaques, increasing the risk of cardiovascular diseases. On the other hand, HDL is the "good" cholesterol that enables the carrying of cholesterol away from the arteries to the liver for metabolism or reuse to lower plaque buildup.

Although cholesterol in itself is not harmful-in fact, it is essential for so many bodily activities-it could become hazardous when changed through oxidation or glycation. For instance, oxidized LDL has been found to invoke inflammatory responses in the body, thus contributing to atherosclerosis, or plaque formation in arteries, which increases the risk of heart disease and stroke. Such glycation, where a glucose molecule attaches itself to a protein or lipid like cholesterol, can disable the function of cholesterol and further accelerate vascular damage in conditions such as diabetes and atherosclerosis. In that respect, whereas intake of appropriate levels of cholesterol is important, reduction in oxidative stress and glycation through diet and lifestyle is likewise crucial for maintaining cardiovascular health.

Myth 4: All calories are equal

Foods can be very different in calorie and nutrient density, an important part of both satiety and health in general. For instance, 100 calories from a candy bar contribute little toward nutritional needs compared to 100 calories from peanuts, which contain healthy fats, fibre, vitamins, and minerals. This difference is just not about reaching one's daily nutritional needs but also about appetite satisfaction and long-term health. TEF: thermic effect of food, specific dynamic action, is the energy used for digestion, absorption, and metabolism of nutrients.

Among the macronutrients, this thermic effect varies: the digestion and metabolism of fat requires the lowest amount of energy; thus, its contribution to the overall calories supplied is only about 2-3%. Carbohydrates have an intermediate thermic effect-their digestion generally uses 5-6% of the calories provided. The digestion and metabolism of proteins are the most expensive, using about 20-30% of their calories. It means that protein-rich food not only enhances metabolism but also helps, concurrently, in the upkeep of muscles when one is on weight loss. In addition, foods high in fibre, protein, and healthy fats feel fuller longer rather than heavy-to-sugar or refined carbs foods, hence bringing down overall calorie intake. For example, meals with whole grains and lean proteins can keep a person full for longer than those meals that would have high contents of simple sugars in them. Another critical factor is the origin of calories, whereby some types of foods-particularly those high in sugars and unhealthy fats-promote oxidation and glycation. Oxidized fat is highly inflammatory and can give rise to cardiovascular disease, while glycated proteins disrupt cellular function and accelerate aging.

Different foods have different hormonal responses: high-sugar foods are associated with spiking levels of insulin, followed by heavy energy crashes and increased hunger not too long after the intake of the food; complex carbohydrates combined with fiber provide slow digestions and less spiking of blood sugar levels. Thus, although the calories may be a measure of energy intake, their source has a very key and determining effect on metabolic effect, satiety, oxidative stress, and hormonal responses. This brings into focus the very important fact that not all calories are created equal. It is about prioritizing nutrient-dense foods over calorie-dense, low-nutrient options that will offer the key to optimized health and well-being.

Myth 5: Eggs raise cholesterol levels

Because of their cholesterol contents, egg yolks for many years were considered damaging. As a result, guidelines were issued that seemed to be grounded on cardiovascular health by limiting the number of eggs that are consumed by people. For rather a long period, it had also been assumed that dietary cholesterol-as in eggs-makes very considerable contributions to higher blood cholesterol levels and hence increases the risk for cardiovascular disease. All this, however, has been countered by modern research proving that dietary cholesterol minimally affects blood cholesterol in the average person. The human body, mainly through the liver, uses a system of feedback-balancing production with dietary intake. If more cholesterol is ingested through diet, the liver generally reduces its production of cholesterol to balance it out and keep blood cholesterol levels fairly stable.

Eggs are also very nutrient-dense food items. Egg yolks especially have a good number of very important vitamins and minerals, which include vitamins A, D, and E, along with calcium, iron, phosphorus, and zinc. Also, egg yolks contain a quantity of antioxidants: choline, lutein, and zeaxanthin, related to brain and eye health. For instance, choline is highly relevant to the activity of the brain and to cell membrane integrity, while lutein and zeaxanthin prevent eye disease by reducing the risk of age-related macular degeneration. This broad nutrient profile would indicate that eggs can form part of a healthy diet, not only because of their supply of protein but also for other health benefits that come with egg consumption.

These are further emphasized by research studies, which highlight that for the majority of people, consuming eggs in moderation does not have a detrimental impact on cholesterol levels. Indeed, as one study revealed, those people who consumed up to 12 eggs a week had similar cholesterol levels to those people who only consume fewer than two eggs a week over a period of four months. Moreover, eggs consumption can increase HDL cholesterol, which is usually referred to as "good" cholesterol and helps clear the LDL or "bad" cholesterol from the blood. The overall effect of this rise in HDL cholesterol is, therefore, heart-healthy since HDL makes it difficult for plaque buildup within the arteries.

Although eggs carry a significant amount of cholesterol, about 186 mg per large egg, recent dietary guidelines reflect a shift in thinking: for most people, dietary cholesterol has less of an impact on blood cholesterol and heart disease risk than previously believed, and current limits on dietary cholesterol no longer exist. Current dietary recommendations instead support reducing saturated and trans fats in the diet. In most cases, eggs can be consumed in a healthy diet without much harm to heart health, provided the consumption of processed foods with unhealthy fats is limited. People with certain health conditions or genetic tendencies that predispose them to high cholesterol should consult with their doctor about specific dietary recommendations. 

Myth 5: Myths on fruits and vegetables

There are several common myths surrounding fruits and vegetables that can lead to misunderstandings about their health benefits and nutritional value. Accordingly, the following opinions deserve attention;

Opinion 1 - All fruits are just sugar

Fruits contain natural sugars such as fructose, but they also provide a wealth of essential nutrients, fiber, and antioxidants that make them a far healthier choice than processed sugary foods. The fiber in fruits plays a vital role in slowing down sugar absorption, which helps regulate blood sugar levels and promotes digestive health. Unlike refined sugars, the fiber in fruits makes them a low-glycemic option, meaning they have a gentler impact on blood glucose. For most people, consuming fruits even in the evening does not cause adverse blood sugar effects, as the natural sugars in fruits are metabolized more gradually, providing a stable energy source.

In addition to fiber, fruits are rich in essential vitamins (such as vitamins C, A, and K) and minerals like potassium, magnesium, and folate, all of which support immune function, cellular repair, and metabolic health. Many fruits are also packed with antioxidants, including flavonoids, polyphenols, and carotenoids, which help combat oxidative stress, reduce inflammation, and lower the risk of chronic diseases. Furthermore, the high-water content in fruits like watermelon and oranges aids in hydration, which is crucial for overall health. Overall, the natural sugars in fruits are balanced by fiber, vitamins, and other beneficial compounds, distinguishing them from the added sugars in processed foods that can spike blood sugar levels and contribute to health issues.

 

Opinion 2 - Eating fruits after 6 pm is harmful

The idea that eating fruits after 6 pm is harmful is largely a myth. This misconception suggests that consuming fruits in the evening might lead to weight gain or other health issues, but there is no scientific evidence to support this claim. The body digests and metabolizes food, including fruits, consistently throughout the day and night, so the timing of fruit consumption does not inherently impact weight, digestion, or nutrient absorption in a negative way. In fact, fruits can be part of a healthy diet at any hour, and their nutritional benefits remain consistent whether eaten in the morning, afternoon, or evening.

Fruits are packed with essential vitamins, minerals, and antioxidants that support health at any time of day. Eating fruits after 6 pm can still provide these nutrients, contributing to immune support, cellular repair, and overall well-being. Additionally, fruits are generally low in calories and high in fiber, making them a good choice for a light evening snack, especially compared to processed foods. They can satisfy sweet cravings naturally, helping prevent overeating and supporting weight management. Therefore, incorporating fruits into your diet after 6 pm is both healthy and beneficial.

 

Opinion 3 - Frozen fruits and vegetables are nutritionally inferior

Freezing is an effective method for preserving the nutritional quality of fruits and vegetables, often making it a smart choice for maintaining nutrient levels. Unlike fresh produce, which can lose nutrients during transport and storage, frozen fruits and vegetables are typically harvested at peak ripeness and quickly flash-frozen, a process that helps retain vitamins and minerals. This rapid freezing preserves nutrients like vitamin C, folate, and certain antioxidants, making frozen options nutritionally comparable, and sometimes superior, to fresh produce that has been stored for extended periods.

In some cases, frozen fruits and vegetables may even be richer in antioxidants, such as polyphenols, lutein, and beta-carotene, due to minimal nutrient loss over time. When selecting produce, frozen options can be a fresher alternative to certain fresh varieties on store shelves, as they avoid the nutrient degradation that occurs with time. Additionally, dried fruits also retain many nutrients and offer a convenient option, though they may have higher sugar concentrations due to the drying process. Overall, frozen and dried produce provide viable, nutritious alternatives to fresh fruits and vegetables, especially when peak freshness is a concern.

 

Opinion 4 - Cooking vegetables diminish their nutritional value

While cooking vegetables can lead to some nutrient loss, particularly of water-soluble vitamins like vitamin C and certain B vitamins, this process also has benefits. Certain nutrients become more bioavailable or easier for the body to absorb after cooking. For instance, cooking tomatoes enhances the bioavailability of lycopene, an antioxidant linked to heart health, and cooking carrots boosts the absorption of beta-carotene. This shows that both raw and cooked vegetables contribute valuable nutrients, and including both in a diet can support overall health.

Moreover, cooking methods can significantly impact nutrient retention. Techniques such as steaming and microwaving help preserve vitamins and minerals while making vegetables easier to digest. This increased digestibility allows the body to absorb minerals and antioxidants more effectively. Thus, while raw vegetables provide certain unique benefits, cooking can improve the nutritional profile of various vegetables, making a balanced mix of both cooked and raw vegetables an ideal approach to gaining a wide spectrum of nutrients.

 

Opinion 5 - All fruits and vegetables are low in calories

Yes, many fruits and vegetables tend to be low in calorie intake, but some types tend to have more calories due to either their natural content of sugars or fats. A good example is that avocados and bananas contain more calories as compared to foods like leafy greens or cucumbers. This does not compromise their nutritional worth but does mean eating portion sizes in mind. The high water and fibre content in most fruits and vegetables contribute to feelings of satiety, and create value for weight management and balanced diets. Produce items that are low in calories include berries, lettuce, and celery. These foods will provide a feeling of fullness with fewer calories.

That said, labelling fruits and vegetables across the board as low-calorie foods can be quite misleading. Vegetables that are starchy, like potatoes, and fruits that have higher calories, such as mangoes, are denser sources of energy. These are still nutrient-dense choices, but the calories accompanying these foods are relatively higher than those from other forms of produce. Thus, portion sizing for these types of foods is helpful in terms of balance, especially in calorie-conscious diets. Fruits and vegetables are generally less calorically dense in the diet compared with processed foods or high-calorie snack foods, and thus the overall health of the person is increased by increasing their presence in the diet.

Both fruits and vegetables are important sources of different and vital nutrient needs and benefits for overall wellness. Fruits are generally higher in vitamins C and A, while vegetables are high in fibre, minerals, and antioxidants-all important for a healthy diet. Cooking actually enhances the bioavailability of several nutrients in vegetables; for example, cooking carrots enhances beta-carotene absorption, and cooking tomatoes enhances lycopene bioavailability. Thus, a range of fruits and vegetables, both raw and cooked, supports a healthy, well-balanced diet.

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KKDS Ranaweera

Chair and Senior Professor of Food Science and Technology
University of Sri Jayewardenepura