Considering Common Nutrition Myths by Christina Badaracco, MPH, RD
Mass marketing campaigns from the food and supplement industries, social media influencers and even friends and family can be sources of unfounded nutrition information and guidance. Hearing myths about nutrition perpetuated by certain researchers or health professionals whose education is outdated and/or based on faulty science is particularly concerning. As a follow-up to our 2021 Insight about common health myths, let's look at the fallacies and evidence base behind four more common nutrition myths.
Small, frequent meals are better for optimal health
Coinciding with the increase in eating food away from home, many people today consume small, frequent meals spread throughout the day instead of three main meals. While their overall caloric intake may be the same, it is distributed across roughly six meals. This tactic is thought to promote satiety, prevent overeating, increase metabolism and maintain energy levels.
However, those benefits don't necessarily hold true for everyone, and they may not be universal. A 2017 review for the American Heart Association concluded that meal frequency doesn't seem to affect energy metabolism (when caloric intake is held constant). While having more frequent meals may help to lower blood pressure and increase HDL (or "good cholesterol"), evidence for impacts on various other biomarkers is mixed. Increasingly, the evidence shows benefits to outcomes such as weight loss and blood sugar control resulting from patterns of time-restricted feeding and intermittent fasting (see this recent article)—which do not align with a more frequent eating pattern. Further, evidence shows it is preferable to eat a smaller meal in the evening and not eat too close to bedtime, which may be difficult to avoid if one eats smaller meals throughout the day (and into the evening).
In reality, individual metabolic rates, chronic condition(s) and lifestyle factors facilitate or hinder a particular eating schedule. People with poor blood sugar control (including those with diabetes) may find that eating smaller and more frequent meals can help to stabilize blood sugar. It may also make it easier for people who have difficulty eating orally or who struggle with low appetite to eat enough throughout the day. People who frequently travel for work and have little time to sit down for a full meal (which may or may not be nutritionally balanced) may also find it more convenient to fit in wholesome "snacks"—even fruits and vegetables—throughout the day.
The most important factor about your eating schedule is that it enables you to eat a balanced diet primarily consisting of unprocessed foods. It's also important to eat with minimal distractions—particularly avoiding screens—so that you can truly enjoy your food and respond to feelings of hunger and satiety. The precise number and schedule of meals are likely not paramount to determining your health. Depending on your goals, though, you may find it helpful to meet with a registered dietitian to help understand and implement the best dietary pattern for your body and lifestyle.
Supplements are a waste of money
Americans spend a lot of money on supplements. A 2021 report from the CDC stated that nearly 58% of American adults had used some type of dietary supplement in the last 30 days. Multivitamins are the most common, followed by vitamin D and omega-3 fatty acids.
It is well known that the FDA only loosely regulates dietary supplements. Companies can begin to sell their products without first testing for safety, quality or efficacy (unlike the clinical trials required of pharmaceuticals). They must only provide "reasonable assurance" that supplements don't pose "a significant or unreasonable risk of illness or injury" when used as directed. (The FDA can remove a supplement from the market if deemed unsafe, though.) So, without some third-party verification, it's impossible to know whether a specific brand's supplement contains what is written on the label.
Extensive data shows that many people are deficient in nutrients like fiber and vitamin D—and the connections between those deficiencies and myriad poor outcomes. However, the evidence base for supplementation to consistently improve outcomes (particularly when an individual is not deficient) is quite mixed. Nutrition research requires studies of sufficient duration to detect effects on health outcomes and ensure any benefits can be sustained; however, those long-term studies are resource-intensive and, therefore, rare.
While it's certainly true that no supplement will be a cure-all, that does not mean supplements are always a waste of money. Factors such as baseline nutritional status, which food or medications are taken (or not taken) with certain supplements, dosage and the quality of a given supplement all play important roles in determining the body's absorption and utilization of a supplement once it is consumed. The most recent position statement from the Academy of Nutrition and Dietetics states that "…micronutrient supplements are warranted when requirements are not being met through the diet alone. Those with increased requirements secondary to growth, chronic disease, medication use, malabsorption, pregnancy and lactation, and aging may be at particular risk for inadequate dietary intakes. However, the routine and indiscriminate use of micronutrient supplements for the prevention of chronic disease is not recommended, given the lack of available scientific evidence." And the most recent recommendation statement from the US Preventive Services Task Force states that more research is needed before making any recommendations regarding the ability of most supplements to prevent cardiovascular disease or cancer. (It does recommend against taking vitamin E and beta-carotene for these purposes, though, based on proven harms.)
So, if you're considering taking one or more supplements, talk with a registered dietitian or primary care physician to ensure you're taking a form of supplement that will be most effective for you. You can also refer to the ConsumerLab, Clean Label Project and US Pharmacopeia websites for information about the quality and safety verifications of different supplements to help you decide which brands to purchase. And keep in mind that no supplement—whether multivitamin, protein, fiber, herbal or anything else—will be fully able to make up for a poor diet.
Foods high in cholesterol are unhealthy
High blood cholesterol is a known risk factor for heart disease. More specifically, low-density lipoprotein, or LDL, is a molecule that carries cholesterol throughout the body. High concentrations—particularly of small, dense LDL molecules—are concerning for heart health.
All animals manufacture cholesterol; therefore, humans make it and consume it in animal-based foods. Foods such as egg yolks, shrimp, liver and high-fat meats are particularly rich sources. Based on the theoretical connection between cholesterol in our food and our blood, health professionals have recommended limiting or avoiding foods containing dietary cholesterol for many decades.
However, new evidence in the last few decades has shown the connection is more complex. Our bodies need cholesterol to complete functions like comprising cell membranes and forming hormones and vitamin D. Therefore, the body closely regulates cholesterol in the blood by controlling its production—i.e., the body makes more when consumption decreases and typically makes less when consumption increases. So, dietary cholesterol is not a direct driver of blood cholesterol for most people. Note that a small percentage of people have a genetic condition—such as familial hypercholesterolemia—that causes them to respond more acutely to dietary cholesterol intake. This specific population is often advised to limit their cholesterol intake.
Instead, dietary trans and saturated fats are the primary drivers of high LDL in our blood. Trans fats are predominantly found in fried foods (the trans fats form in the oil during prolonged boiling) and commercial baked goods. Meat, eggs and tropical oils are leading sources of saturated fats. Not all saturated fats lead to increased LDL—and for those that do, the link to resulting heart disease is debated—but it is still advisable to keep portions small and opt for healthier oils as often as possible.
Thus, the cholesterol in animal-based foods is not implicated in driving heart disease. Unfortunately, some physicians continue to recommend that patients limit cholesterol and food companies tout their cholesterol-free products as being healthier when this is not warranted. Cholesterol-containing foods can be harmful and raise the risk of heart disease, though, when 1) cooked at high temperatures (they form inflammatory molecules called oxysterols) and 2) conversion occurs of other components in animal-based foods into molecules called TMAO by our microbiota (refer to this previous article). Therefore, if you consume animal-based foods, it's best to eat them only occasionally, keep portions small and avoid cooking them over high heat for prolonged periods.
Plant-based meat and dairy alternatives are healthier choices
Improving health and reducing disease risk are among the top motivating factors for the increasing numbers of people following vegetarian or vegan diets. To meet this demand, companies are selling products made from isolated soy, wheat or pea proteins that are combined with myriad oils, gums, fibers, sugar and/or salt. They promote these products as healthier alternatives—thereby helping to fuel the rise of plant-based versions of dairy and meat (see this recent article).
Eating a more plant-forward diet benefits most people's health, but that does not necessarily mean that all alternative products are healthier than their animal-based counterparts. Consider what may be included in plant-based alternatives:
Plant-based milks can be much lower in essential nutrients like calcium, vitamin D and protein; even if the products are fortified, the micronutrients may not be as bioavailable.
Some milks have nearly 20 grams of sugar per cup—80% of what the American Heart Association recommends for women and children daily.
Many plant-based cheeses contain just as much saturated fat and sodium as dairy cheeses, providing essentially empty calories and increasing the risk of high blood pressure.
Plant-based meats can contain up to six times more sodium and three times more saturated fat than real meat.
Bulking agents such as cellulose, genetically modified soy derivatives, refined sugar, oils (including palm oil) and starches may be included.
Meat may contain negligible amounts of key vitamins and minerals (such as zinc).
Also, while there are many benefits to consuming a vegetarian or vegan diet, they aren't necessarily the best choice for everyone. Older adults, people experiencing hypermetabolism due to injury or some acute conditions and certain other populations may find it impossible to consume enough key nutrients from plant-based sources.
Preliminary research shows that plant-based meats may be preferable for heart health. However, long-term studies are still needed to assess the cumulative health effects over time and on different organ systems. Also, plant-based diets can be full of refined carbohydrates and oils and may be eaten in excessively large portions. Therefore, when considering plant-based alternatives to dairy and meat, try following these suggestions:
Choose the products with the shortest ingredients list and the least added oil, sugar and salt. Also, opting for an alternative product with roughly the same amount of protein can help ensure you consume enough.
When possible, make your own version at home. For example, soaked and blended cashews can make a delicious sweet or savory cheese substitute, and combinations of crumbled tofu or tempeh, chopped walnuts, lentils and mushrooms can make an umami-rich ground meat substitute.
It's especially important for anyone being treated for a chronic condition, recovering from injury and/or taking medications that may impair absorption or deplete certain micronutrients (such as steroids, statins or ACE inhibitors) to talk with a registered dietitian about your dietary intake to ensure you're meeting your body's needs. (Of course, anyone could benefit from meeting with a dietitian!)
We hope this article provides plenty of useful information and references for you to investigate further. Please share what you've learned with your friends and family to help clear up any confusion and ease them on a path to healthier habits. For more information about the latest nutrition science and recommendations, refer to resources such as the Berkeley Wellness Letter, Harvard Nutrition Source, and the websites of the Academy of Nutrition and Dietetics and the True Health Initiative.
Resources for this article can be found here.
Christina Badaracco, MPH, RD
Christina is a registered dietitian and author who aims to improve access to healthy and sustainable food and educate Americans about the connections between food and health. She loves to experiment with healthy recipes in the kitchen and share her creations to inspire others to cook.
Christina completed her dietetic internship at Massachusetts General Hospital and earned her Master of Public Health degree from the University of California, Berkeley. Previously, she graduated with a degree in Ecology and Evolutionary Biology from Princeton University, after conducting her thesis on sustainable agriculture and energy in Kenya. She has done clinical nutrition research at the National Institutes of Health, menu planning and nutrition education at the Oakland Unified School District and communications at the Environmental Protection Agency's Office of Water. She has also enjoyed contributing to children’s gardens, farmers markets and a number of organic farms.