Five Snacks to Beat 3 O'Clock Slump

It's a few hours after lunch and that late afternoon energy slump is setting in. But don't head for the coffee or the candy machine looking for a boost—there are far healthier snacks that'll energize you without packing on the pounds or keeping you up at night. And better yet, they include foods that contain an unsaturated fat that can help postpone future attacks of the munchies. A few of our favorites:

1. Olive Oil: Sounds crazy, but olive oil is actually full of an unsaturated fat that'll keep you full longer. According to a study recently published in the journal Cell Metabolism, once oleic acid reaches the intestine, it's converted into a hormone that helps fend off the next wave of hunger pangs. Try dipping high-fiber bread in olive oil instead of using butter, or have a couple of olives on crackers, says Jenn Stokols, a registered dietician and the nutritionist at Nova Medical Group in Virginia.

2. Nuts: We all know that almonds, peanuts and walnuts make a great, healthy snack—they contain oleic acid and are full of protein, which provides long-lasting energy and helps build muscles and bones. But go a little crazy—add high-fiber cereals and a couple of sweets to make homemade trail mix, or experiment with nut butters; you can upgrade the traditional peanut butter and jelly sandwich with almond or even macadamia nut butter.

3. Low-Fat Dairy: Things like yogurt, string cheese and cheese on high-fiber crackers are great sources of protein and calcium, Stokols says. You can even try a mini pizza—half of an English muffin with sauce and mozzarella cheese, heated or not. "The key is mini, small portions," she says.

4. Anything Avocado: "Avocado makes a wonderful sandwich," Stokols says. "It's almost a condiment. Because of its creamy texture, it can take the place of mayonnaise. With a turkey sandwich, instead of the cheese, which might be slightly higher in fat, use avocado slices." Avocadoes also happen to be high in oleic acid, and they're good sources of potassium and the heart-healthy nutrient folate.

5. Dressed-Up Vegetables: Celery and carrots are go-to snacks, but can be boring, Stokols says. Just as filling, and a little more fun, are roasted vegetables: put sliced or whole vegetables on a baking sheet with a thin coating of olive oil, then roast them at 400 degrees for 45 minutes to an hour. "It gets almost caramelized and sweet," she says. And you can reheat them at work with the microwave.