Just as it's not healthy to be overweight, being underweight can be a problem, too - putting you at risk for malnutrition and problems like osteoporosis later in life. But there's definitely a right and a wrong way to do it. You don't want to add foods high in sugar and fat that can increase your risk for heart disease, high cholesterol, and diabetes, not to mention affect your energy level and mood.

It's ok to eat carbs - they're not all created equal, after all. Opt for whole-wheat breads and whole-grain cereals, which are calorie-dense sources of fiber and disease-fighting phytochemicals and antioxidants. Look for breads that have about 100 calories per slice. Arnold's Grains & More breads are made with 100 percent whole-wheat flour and come in varieties such as Double Protein (110 calories, 3 grams of fiber, and 7 grams of protein per slice) and Double Fiber (90 calories and 5 grams of fiber per slice). As for cereal, try Fiber One Caramel Delight, which tastes like Cinnamon Toast Crunch but has 180 calories and 9 grams of fiber per cup. For something less sweet, try Quaker Oatmeal Squares Cereal (1 cup has 210 calories and 5 grams of fiber). Add sliced bananas and low-fat milk for a hearty, healthy breakfast or a great midday snack.

Enjoy some heart-healthy fats like olive oil, canola oil, salmon and nuts. These foods pack a calorie punch without the artery-clogging fats of creamy, fried, and greasy foods - in fact, they can even reduce your risk of heart disease. It's easy_ For a daytime snack, munch on some almonds or walnuts. For dinner, try broiling a 6-ounce filet of salmon drizzled with olive oil, salt and pepper and sauteing a side of spinach with garlic and a tablespoon of olive oil.

Pack in the protein. While eating fats and carbs will add pounds, our bodies need protein to help maintain and build muscle mass. Go for lean protein like grilled chicken breast, white meat turkey, egg whites and seafood. For an extra boost, add protein powder to fruit smoothies.

Other quick tips for adding healthy calories: • Sprinkle walnuts or almonds into your morning bowl of cereal • Add a cup of whole-wheat pasta or brown rice to your dinner • Toss together your own trail mix. Combine almonds (or any other nut), high-fiber cereal , dried fruit and semi-sweet chocolate chips, and put it in small bags for a go-to snack any time of the day. Get creative and add your own twist to the mix! • 1/2 whole-wheat bagel with peanut butter and sliced banana • Create your own pizza, Tortilla pizza (whole-wheat, high-fiber tortilla with low-fat mozzarella and tomato sauce)

Tanya Zuckerbrot, MS, RD is a nutritionist and founder of

www.Skinnyandthecity.com

. She is also the creator of The F-Factor DietaC/, an innovative nutritional program she has used for more than ten years to provide hundreds of her clients with all the tools they need to achieve easy weight loss and maintenance, improved health and well-being. For more information log onto

www.FFactorDiet.com

.

Tanya Zuckerbrot MS, RD, is a Registered Dietitian in New York City and the author of two bestselling diet books: The F-Factor Diet and The Miracle Carb Diet: Make Calories and Fat Disappear – with Fiber.

Subscribe to Tanya’s FREE Weekly Newsletter and follow her on Instagram, Facebook, Twitter and Pinterest. To learn more about Tanya’s private nutrition counseling services visit www.ffactor.com.