Recently, a friend who was eating with me appeared shocked as I spread full-fat natural peanut butter on my whole-wheat toast. Isn’t peanut butter super-fattening, she asked? It’s high in fat but that doesn’t mean it’s fattening, I told her, noting that gaining or losing weight, and body fat, basically comes down to balancing calories. Knowing my master’s work focused on weight loss, she took my word on this. (Find easy, quick and delicious 500-Calorie Dinners to help you lose .)
That said, peanut butter is a concentrated source of calories, so you don’t want to go overboard. But you don’t need to eat tons of the stuff to feel satisfied: just a tablespoon (90 calories) or two of peanut butter goes a long way. I eat peanut butter nearly every day because it tastes so good and it’s really nutritious. Peanut butter provides protein and folate, a B vitamin important for the healthy development of new cells. (See the winners of our Natural Peanut Butter Taste Test. )
As a nutritionist, I often encounter people who fear healthful foods because these foods have somehow gotten bad reps they just can’t shake. Peanut butter  is a common one. Here are four more “misunderstood” foods and why you should eat them—in moderation, of course.
The bad rep: A significant source of dietary cholesterol, egg yolks are off-limits for those concerned about heart health.
The good truth: Medical experts now emphasize that saturated fats and trans fats are bigger culprits in raising blood cholesterol than dietary cholesterol is. Plus, eggs are super-satisfying: in one study, people who ate a scrambled-egg-and-toast breakfast felt more satisfied, and ate less at lunch, than they did when they ate a bagel that had the same number of calories. Egg yolks contain lutein and zeaxanthin, compounds that research links with reduced risk for age-related macular degeneration (AMD), the leading cause of blindness in people over 50. (Need new ideas for eggs? Find dozens here .)
The bad rep: Beef is full of saturated fat and dietary cholesterol, so people who care about their hearts should avoid it.
The good truth: Lean cuts of beef are a low-fat source of protein and iron, a mineral essential for getting oxygen from the lungs to cells throughout the body—and one many women (of childbearing age) are deficient in. There are many lean cuts of steaks: filet mignon, sirloin, strip steak, flank steak. If you can’t remember the names, pick steaks that are deep red with a relatively small amount of marbling—a fancy name for fat—to find lean cuts. Click here for a Bistro Flank Steak Sandwich that has only 3 grams of saturated fat per serving! 
The bad rep: Chocolate has lots of fat, lots of sugar—and it tastes amazing, so it must be bad for you.
The good news: Dark chocolate contains flavanols, antioxidants that seem to have a blood-thinning effect, which can benefit cardiovascular health. And, recently, researchers in Switzerland reported that eating dark chocolate (1.4 ounces of it) every day for two weeks reduced stress hormones, including cortisol, in highly stressed people. But be sure to account for the calories (1.4 ounces delivers 235)—or you may be stressed to see extra pounds creeping on. (Discover delicious chocolate recipes here .)
The bad rep: Potatoes rank high on the glycemic index, which measures how quickly different foods raise your blood sugar. Foods with a high GI value tend to cause a higher spike in blood sugar—and in insulin, the hormone that helps glucose get into cells—which can be a problem for some people, particularly those with diabetes.
The good news: Potatoes are a good source of fiber, potassium and vitamin C. And unless you’re eating an absolutely plain potato all by itself, its GI value doesn’t matter. (It’s also worth noting that the glycemic index is an imperfect and controversial scale.) A high-GI potato becomes a low-GI meal if you simply add a little olive oil, because the added fat helps slow the absorption of the potato’s carbohydrates. (Try our easy, delicious recipe for Oven-Fried Potatoes .)
Pictured: Chocolate & Nut Butter Bites 
What food myth have you bought into? Tell us what you think below.