You’ve probably heard the “5-second rule,” the notion that if you pick up dropped food quickly, it remains germ-free. Actually, a high school student busted this myth in 2003, with a simple study involving gummy bears and cookies.
When Jillian Clarke put these foods on floor tiles infected with E. coli bacteria for five seconds, then analyzed the food for bacteria, she found that in all cases, the food was contaminated, putting anyone who ate it at risk for a nasty case of food poisoning. The teen’s research was honored by the Annals of Improbable Research with the 2004 Ig Nobel Prize in public health, the New York Times reports.
A more elaborate study, involving tiles, carpet and wood infected with Salmonella, and slices of bread and bologna, found that bacteria can survive on these surfaces for up to four weeks in large enough quantities to make people sick. What’s more, salmonella is transferred to food almost instantly on contact, researchers from Clemson University report.
Here’s a look at other common food myths.
Myth #1: Raw Foods Are Always More Nutritious than Cooked Ones
Fact: While followers of raw-food diets claim that eating uncooked food preserves all of the nutrients, research shows that this idea is half-baked. It’s true that heat destroys certain water-soluble vitamins, such as vitamin C, but cooking boosts levels of other nutrients.
For example, ketchup and tomato sauce contain up to six times more lycopene than raw tomatoes. Several studies show that this powerful antioxidant reduces risk for prostate and colon cancer, as well as heart disease. And since lycopene is fat-soluble, you need to eat cooked tomatoes with some fat (such as olive oil) to help absorption.
Myth #2. Skipping a Meal Slows Your Metabolism
Fact: Missing a single meal does not put your body into “starvation mode,” but may cause you to eat more at the next meal, because you’re hungrier. Research shows that it actually takes about two to three weeks of consistently low-calorie intake or at least 24 hours of eating absolutely nothing before there’s any significant change in your metabolic rate.
One study found after one to three days of total starvation, there’s a temporary rise in basal metabolic rate, while prolonged starvation lowers it, with the sharpest drop in obese people (explaining why it’s often difficult for very overweight people to slim down even on a very low-calorie diet).
Myth #3: High-fructose Corn Syrup is Worse than Sugar
Fact: The idea of that high-fructose corn syrup (HFCS) is particularly harmful is “one of those urban myths that sounds right, but is basically wrong,” says the Center for Science in the Public Interest, a health advocacy group. In reality, both table sugar and HFCS are almost identical, nutritionally, with similar effects on the body’s levels of insulin, blood glucose, triglycerides, and hunger hormones.
The real problem isn’t the type of sweetener we eat, but the fact that Americans are consuming way too many empty calories, a key culprit in the obesity epidemic. The American Heart Association recommends a maximum of six spoonfuls of sugar for women, and nine for men, without singling out any specific type, such as HFCS, as the sole dietary villain. Any food ingredient ending in “ose” is usually a form of sugar.
Myth #4: Fruit Juice is Healthy
Fact: While an apple a day may keep the doctor away, that’s not true of apple juice or other fruit beverages. While many people consider fruit juice a healthier option than soda, data from the Harvard Nurses' Study found that women who drink one or more glasses of fruit juice a day are more likely to develop type 2 diabetes.
Conversely, the researchers found that women who eat three servings of fruit or vegetables a day had significant lower risk of diabetes than did those who ate fewer servings. Not only does eating fruit and vegetables provide healthy fiber and vitamins, but they’re filling, reducing the risk of weight gain (which in turn, raises diabetes risk.)
Myth #5: You Need a High-Protein Diet to Build Muscle Mass
Fact: To bulk up, you need weight training plus extra calories. However, there’s no need to gulp down high-protein shakes and meat galore—a myth that’s been circulating since the 6th century BC, with an ancient Greek strongman claiming that the secret of his athletic prowess was eating 20 pounds of beef a day.
While protein is a crucial nutrient for building, maintaining and repairing body tissues, a very high-protein diet boosts the threat of heart disease, impaired kidney function, bone fractures, and some cancers, including those of the colon and breast, according to Physicians for Responsible Medicine. In the typical Western diet, most people eat at least double the amount of protein needed for good health.
The American Academy of Nutrition and Dietetics advises people who are training for resistance sports, including weight lifting, to limit themselves to no more than 0.55 to 0.77 grams of protein per pound of body weight, as part of a healthy diet that also includes healthy carbs for energy and about 20 to 35 percent fat.