It goes like this: A client looking to lead a healthier life hires me, a nutritionist, to help him improve his diet. I analyze what he’s been eating, factor in his food preferences, and together we create an eating plan that fits his lifestyle and goals.
Soon after, he’s noticeably leaner and more energetic—a happy customer.
That’s when the trouble starts. After a coworker asks him for the details of his diet, my client suddenly finds himself in a heated interrogation. Doesn’t your nutritionist know red meat causes cancer? And that potatoes cause diabetes? Shouldn’t he tell you to eat less salt, to prevent high blood pressure?
The upshot: Myths just made my job a lot harder.
That’s because nutrition misinformation fools men into being confused and frustrated in their quest to eat healthily, even if they’re already achieving great results.
Thankfully, you’re about to be enlightened by science. Here are five food fallacies you can forget about for good.
High Protein is Harmful
The origin: Back in 1983, researchers first discovered that eating more protein increases your “glomerular filtration rate,” or GFR. Think of GFR as the amount of blood your kidneys are filtering per minute.
From this finding, many scientists made the leap that a higher GFR places your kidneys under greater stress.
What science really shows: Nearly 2 decades ago, Dutch researchers found that while a protein-rich meal did boost GFR, it didn’t have an adverse effect on overall kidney function.
In fact, there’s zero published research showing that downing hefty amounts of protein—specifically, up to 1.27 grams per pound of body weight a day—damages healthy kidneys.
The bottom line: As a rule of thumb, shoot to eat your target body weight in grams of protein daily.
For example, if you’re a chubby 200 pounds and want to be a lean 180, then have 180 grams of protein a day. Likewise if you’re a skinny 150 pounds but want to be a muscular 180.
Sweet Potatoes are Better
The origin: Because most Americans eat the highly processed version of the white potato—for instance, french fries and potato chips—consumption of this root vegetable has been linked to obesity and an increased diabetes risk.
Meanwhile, sweet potatoes, which are typically eaten whole, have been celebrated for being rich in nutrients and also having a lower glycemic index than their white brethren.
What science really shows: White potatoes and sweet potatoes have complementary nutritional differences; one isn’t necessarily better than the other.
For instance, sweet potatoes have more fiber and vitamin A, but white potatoes are higher in essential minerals, such as iron, magnesium, and potassium.
As for the glycemic index, sweet potatoes are lower on the scale, but baked white potatoes typically aren’t eaten without cheese, sour cream, or butter. These toppings all contain fat, which lowers the glycemic index of a meal.
The bottom line: The form in which you consume a potato—for instance, a whole baked potato versus a processed potato that’s used to make chips—is more important than the type of spud.