Myth No. 6: White potatoes are bad for you.
Potatoes have often been vilified in the nutrition community 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, said Daphene Altema-Johnson, a program officer of food communities and public health at the Johns Hopkins Center for a Livable Future. They are rich in vitamin C, potassium, fiber and other nutrients, especially when consumed with the skin. They are also inexpensive and found year-round in grocery stores, making them more accessible. Healthier preparation methods include roasting, baking, boiling and air frying.
Myth No. 7: You should never feed peanut products to your children within their first few years of life.
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, like peanuts or eggs, during their first few years of life. But now, allergy experts say, it’s better to introduce peanut products to your child early on.
If your baby does not have severe eczema or a known food allergy, you can start introducing peanut products (such as watered-down peanut butter, peanut puffs or peanut powders, but not whole peanuts) at around 4 to 6 months, when your baby is ready for solids. Start with two teaspoons of smooth peanut butter mixed with water, breast milk or formula, two to three times a week, said Dr. Ruchi Gupta, a professor of pediatrics and the director of the Center for Food Allergy & Asthma Research at the Northwestern Feinberg School of Medicine. If your baby has severe eczema, first ask your pediatrician or an allergist about starting peanut products around 4 months. “It is also important to feed your baby a diverse diet in their first year of life to prevent food allergies,” Dr. Gupta said.
Myth No. 8: The protein in plants is incomplete.
“‘Where do you get your protein?’ is the No. 1 question vegetarians get asked,” said Christopher Gardner, a nutrition scientist and professor of medicine at Stanford University. “The myth is that plants are completely missing some amino acids,” also known as the building blocks of proteins, he said. But in reality, all plant-based foods contain all 20 amino acids, including all nine essential amino acids, Dr. Gardner said; the difference is that the proportion of these amino acids 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 throughout the day — such as beans, grains and nuts — and eat enough total protein. Luckily, most Americans get more than enough protein each day. “It’s easier than most people think,” Dr. Gardner said.
Myth No. 9: Eating soy-based foods can increase the risk of breast cancer.
High doses of plant estrogens in soy called isoflavones have been found to stimulate breast tumor cell growth in animal studies. “However, this relationship has not been substantiated in human studies,” said Dr. Frank B. Hu, a professor and the chair of the department of nutrition at the Harvard T.H. Chan School of Public Health. So far, the science does not indicate a link between soy intake and breast cancer risk in humans. Instead, consuming soy-based foods and drinks — like 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, fiber, vitamins and minerals,” Dr. Hu said. The research is clear: Feel confident incorporating soy foods into your diet.
Myth No. 10: Fundamental nutrition advice keeps changing — a lot.
This is not the case, said Dr. Marion Nestle, a professor emerita of nutrition, food studies and public health at New York University. “In the 1950s, the first dietary recommendations for prevention of obesity, Type 2 diabetes, heart disease and the like advised balancing calories and minimizing foods high in saturated fat, salt and sugar. The current U.S. Dietary Guidelines urge the same.” Yes, science evolves, but the bottom-line dietary guidance remains consistent. As author Michael Pollan distilled to seven simple words: “Eat food. Not too much. Mostly plants.” That advice worked 70 years ago, and it still does today, Dr. Nestle said. And it leaves plenty of room for eating foods you love.