Think fast: What have your last few snacks -- at work, at home, before bed -- consisted of? If more often than not you're reaching for sugary sweets, caffeinated beverages, or fast-food options, your between-meal bites could be bringing down your diet, your mood, and your productivity.

You can get the most out of your snacks by choosing foods that naturally have the fuel to keep you going and the nutrients to help you feel satisfied. Stock your cabinets and your fridge with the following power snacks, and you'll never go hungry again. 

Next time you're hungry, reach for a nut. Bite for bite they're one of the most nutrient-dense foods you can eat. An excellent alternative to meat as a source of protein, most nuts are low in saturated fat yet high in good-for-you mono- and polyunsaturated fats. They also don't contain cholesterol; instead, they have phytosterols, which research has shown to be heart-healthy.

Another way to enjoy the benefits of nuts: Pair a nut butter -- peanut, almond, or cashew, for example -- with a piece of fruit or some whole-grain bread.

It's hard to improve on Mother Nature's perfect snack: Whole fruits like apples, pears, peaches, oranges, and bananas (to name a few) are sweet and delicious, less than 100 calories a piece, and usually don't require extra packaging. And their natural sugars will give you a longer burst of energy than the refined sugars in cookies and candy.

Serve them as crudite at a party, pack them in your lunch, or munch on them on your next road trip. Crunchy veggies like carrots, celery, bell peppers and cucumbers (both technically fruits), and cauliflower are the perfect accompaniment to hummus, guacamole, and vinaigrettes. Eating vegetables with a little bit of healthy fats can help your body better absorb their nutrients.

An easy way to make your snacks more nutritious is to swap refined carbs -- basically anything made from white flour -- with whole-wheat or whole-grain varieties. This will up the fiber content, which can help you feel fuller longer. Look for whole-grain pretzels, crackers, and even cookies to pair with healthy dips or nut butters.

Dairy products made with 1-percent or skim milk are a great source of calcium, plus they're full of protein that can keep you from feeling hungry again in an hour. And yogurt will help build up your gut's supply of probiotics -- friendly bacteria known to fight inflammation.

Enjoy a cup of yogurt with fresh fruit, granola, or whole-grain cereal sprinkled on top, or mix it into a smoothie. Avoid whole-milk dairy products, however, which are full of saturated fat.

Avocados are proof that nature loves us: As rich and creamy as a dessert, they're also loaded with nutrients like potassium and folate.

The time-honored way to enjoy them is mashed into guacamole, but you can also add them to a shake, spread them on a piece of whole-grain toast, or enjoy a slice solo, with a little bit of salt and lime juice. They're high in fat (the good kind!) and calories, however, so remember that a little bit goes a long way.

While those heart-shaped boxes of milky, cream-filled bonbons don't qualify, recent studies show that pure dark chocolate is actually good for you. That doesn't mean you should stack a massive supply next to the remote control and settle in for the winter. But in moderation, you can enjoy the glorious taste of dark chocolate guilt-free.

Most store-bought granolas are high in sugar, but if you read labels carefully -- or make your own -- this favorite snack food can make for a satisfying and nutritious mini-meal.

Hummus is a spread made from olive oil and chickpeas, a meatless source of protein and fiber. It makes a delicious topping for raw veggies or whole-wheat pita bread. 

The next time you're hungry, sip a cup of green tea instead of diving into a high-calorie snack. If your cravings are coming more from thirst or boredom, this may be all you need to satisfy them. Green tea is low in caffeine but high in antioxidants -- and research shows that it may actually help speed up your metabolism so the body can burn more calories.