10 Nutrition myths and what you should know instead

18th Dec 2023 Wellbeing

5 min read

Health experts dispel nutrition myths that we all hear about and instead offer insight into what's actually good and bad with our diets for our bodies

MYTH 1: Fresh fruits and vegetables are always healthier than canned, frozen or dried varieties

Despite the enduring belief that “fresh is best,” research has found that frozen, canned and dried fruits and vegetables can be just as nutritious as fresh.

“They can also be a money saver and an easy way to make sure there are always fruits and vegetables available at home,” says Sara Bleich, a professor of public health policy at Harvard University.

One caveat: Some canned, frozen and dried varieties contain added sugars, saturated fats and sodium, so be sure to read nutrition labels, especially on prepared foods. Choose the ones that keep those ingredients to a minimum.

MYTH 2: All fat is bad

Avocados contain healthy, monounsaturated fats. Credit: K Synold

When studies published in the late 1940s found correlations between high-fat diets and high levels of cholesterol, experts reasoned that if you reduced the amount of total fats in your diet, your risk for heart disease would go down. The assumption was that a low-fat diet could benefit everyone, even though there was no solid evidence that doing so would prevent heart disease, obesity and other health issues.

As a result, says Vijaya Surampudi, an assistant professor of medicine at the University of California, Los Angeles, Center for Human Nutrition, many people—and food manufacturers—replaced calories from fat with calories from refined carbohydrates such as white flour and added sugar.

“Instead of this helping us stay slim, rates of overweight and obese people went up significantly,” she says.

In reality, not all fats are bad. While certain types, including trans fats, can increase your risk for heart disease or stroke, healthy fats help reduce your risk. Examples of those include monounsaturated fats (olive oil, avocados, some nuts and seeds) and polyunsaturated fats (sunflower oil, fish, flaxseed).

Good fats also supply energy, produce important hormones, support cell function and aid in the absorption of some nutrients.

If you see a product labelled “fat-free,” don’t assume it is healthy, Surampudi says. Prioritize products with simple ingredients and no added sugars.

MYTH 3: “Calories in, calories out” is the most important factor for maintaining weight

It’s true that if you consume more calories than you burn, you will proba- bly gain weight. And if you burn more calories than you consume, you will probably lose weight—at least for the short term.

But research does not suggest that eating more will result in becoming overweight or obese.

"Maintain a healthy weight by shifting from counting calories to prioritising healthy eating overall"

“Rather, it’s the types of foods we eat that may be the long-term drivers” of those conditions, says Dariush Mozaffarian, a professor of nutrition and medicine at Tufts University in Massachusetts. Ultraprocessed foods—such as refined starchy snacks, cereals, crackers, energy bars, baked goods, sodas and sweets—can lead to weight gain. That’s because they are rapidly digested and flood the bloodstream with glucose, fructose and amino acids, which the liver converts to fat.

Instead, the best way to maintain a healthy weight is to make the shift from counting calories to prioritising healthy eating overall. Go for quality over quantity.

MYTH 4: People with type 2 diabetes shouldn’t eat fruit

Eating fruits like blueberries can actually help control your blood sugar. Credit: K Synold

While fruit juices can raise blood sugar levels because of their high sugar and low fibre content, research has found this isn’t the case with whole fruits. Some studies show, for instance, that those who consume a serving of whole fruit per day (particularly blueberries, grapes and apples) have a lower risk of developing type 2 diabetes.

And other research suggests that if you already have type 2 diabetes, eating whole fruits can help control your blood sugar.

It’s time to bust the myth, says Linda Shiue, director of culinary medicine and lifestyle medicine at Kaiser Permanente San Francisco. She says that everyone—including those with type 2 diabetes—can really benefit from fruit’s health-promoting vitamins, minerals, antioxidants and fibre.

MYTH 5: Plant beverages are healthier than dairy milk

Kathleen Merrigan, professor of sustainable food systems at Arizona State University and a former US deputy secretary of agriculture, disagrees. She says that while the nutrition of plant-based beverages can vary, many have more added ingredients— such as sodium and added sugars, which can contribute to poor health—than cow’s milk.

Consider protein: Typically, cow’s milk has about eight grams of protein per 250 millilitres, whereas almond beverage typically has one or two grams in the same amount. Oat beverage usually has around two or three grams.

MYTH 6: Potatoes are bad for you

Potatoes can actually be healthy and are rich in nutrients. Credit: K Synold

Potatoes have been vilified because of their high glycemic index, which means they contain rapidly digestible carbohydrates that can spike your blood sugar. However, potatoes can actually be beneficial for health, says Daphene Altema-Johnson, a program officer of food communities and public health at Johns Hopkins University.

Potatoes are rich in vitamin C, potassium, fibre and other nutrients, especially when consumed with the skin on. They are also inexpensive and available year-round. The healthiest ways to prepare them include baking and boiling.

MYTH 7: Never feed peanut products to little kids

For years, experts told new parents that the best way to prevent their children from developing food allergies was to avoid feeding them common allergenic foods, such as peanuts or eggs, during their first few years of life. But now, allergy experts say, it’s better to introduce peanut products early on.

"Now allergy experts say it’s better to introduce peanut products early on"

If your baby doesn’t have severe eczema or a known food allergy, you can start introducing peanut products (such as peanut powders or watered-down peanut butter, but not whole peanuts) when they are four to six months old, around the time your baby is ready for solids.

Start with ten millilitres of smooth peanut butter mixed with water, breast milk or formula two to three times a week, says Ruchi Gupta, director of the Center for Food Allergy & Asthma Research at Northwestern University in Illinois. “It’s also important to feed your baby a diverse diet in their first year to prevent food allergies,” Gupta says.

MYTH 8: The protein in plants is incomplete

“‘Where do you get your protein?’ is the most common question vegetarians are asked,” says Christopher Gardner, a nutrition scientist and professor of medicine at Stanford University in California. “The myth is that plants are completely missing some amino acids,” also known as the building blocks of proteins, he adds. But in reality, all plant-based foods contain all 20 amino acids, including the nine essential ones. The difference is that the proportion isn’t as ideal as the proportion of amino acids in animal-based foods.

So to get an adequate mix, you simply need to eat a variety of plant-based foods—such as beans, grains and nuts—through the day, and eat enough total protein.

“It’s easier than most people think,” Gardner says.

MYTH 9: Eating soy can increase breast cancer risk

Edamame and other soy-based foods can actually help prevent breast cancer. Credit: K Synold

High doses of plant estrogens in soy, called isoflavones, have been found to stimulate breast tumour cell growth in animal studies.

“However, this relationship has not been substantiated in human studies,” says Frank B Hu, chair of the department of nutrition at the Harvard TH Chan School of Public Health. So far, the science does not indicate a link between soy and breast cancer risk in humans. Instead, consuming soy-based foods and drinks—including tofu, tempeh, edamame, miso and soy milk—may even have a protective effect toward breast cancer risk and survival.

“Soy foods are also a powerhouse of beneficial nutrients related to reduced heart disease risk, such as high-quality protein, fibre, vitamins and minerals,” Hu says.

MYTH 10: The best nutrition advice keeps changing

Not true, says Marion Nestle, a professor emerita of nutrition, food studies and public health at New York University. In the 1950s, she explains, the first dietary recommendations for prevention of obesity, type 2 diabetes, heart disease and other ailments advised balancing calories and minimising foods high in saturated fat, salt and sugar. That is still the case today.

"Science evolves, but the bottom-line guidance remains consistent"

Yes, science evolves, but the bottom-line guidance remains consistent. As famed author Michael Pollan put it: “Eat food. Not too much. Mostly plants.” That advice leaves plenty of room for eating foods you love.

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