Losing weight means you have to exercise more or eat less, or a combination of the two. Want to stick to your diet? Start snacking. It helps control hunger and rein in portion sizes at meals. Regular snacks can stop you from feeling hungry between meals and help maintain a steady level of blood glucose -- vital for preventing cravings and dips in your energy levels or mental alertness. The best snacks are ones that include healthy nutrient dense foods. Unprocessed whole foods make incredible snacks to fuel your body throughout the day and provide the energy you need to perform at optimal levels.

1. Sunflower seeds are like a cousin to the nut and contain a lot of the same good characteristics. If you choose to eat these, be sure to choose the ones with low or no salt. Many people like to lick the salt from the shell and that's when a healthy snack turns into a not-so-healthy snack.

2. Hard-boiled eggs are a very portable weight-loss snack. Rich in protein, essential fats and vitamins, hard-boiled eggs are filling and easy to prepare. Leave the eggs inside their shells and peel when you are ready to eat them to maintain their freshness.

3. Tuna, an excellent source of lean protein, vitamins and minerals. Tuna can also help lower blood pressure and cholesterol. Research has shown that omega-3 fatty acids can help lower the risk of heart disease, ease the pain of arthritis, reduce asthma complications, and is essential in the growth and development of young children.

4. Ditching the celery sticks doesn't mean abandoning the whole food group. Frozen vegetables often taste better because they're not turning into starch, like their produce-aisle counterparts. Freezing vegetables seals in their naturally sweet flavor. Half of a cup of peas has 55 calories and 3 g of fiber; the same amount of corn contains 72 calories with 2 g of fiber. The high-fiber and low-calorie-density combination means they're filling and satisfying, and the frozen part makes them interesting. They're firm, but not rock hard, and they melt in your mouth.

5. An 8-ounce cup of yogurt generally contains 2-3 grams of fat and around 150 calories. This is a much better snack food option than something like ice cream. A recent study showed people that consumed three servings of light yogurt daily as part of a reduced-calorie diet lost about 20 percent more weight than those who only cut calories. This is one of the best natural weight loss.

6. Although nuts can be calorie dense, they contain healthy omega-3 and omega-6 fats, fiber, vitamins and minerals. Nuts are a filling and healthy snack. If you choose nuts as a snack, eat them raw and unsalted in small quantities--for example, 10 almonds or five Brazil nuts. Avoid nuts if you have any form of nut allergy.

7. The nutritional stars in apples (fiber, flavonoids, and fructose) translate into apples' ability to keep us healthy. Apples are a good source of dietary fiber and vitamin C. Most of the apple's fiber is contained in its skin, as is the majority of its quercitin. Unfortunately, in conventionally grown apples, the apple skin is also the part most likely to contain pesticide residues and may have toxic residues if covered in petroleum-based waxes. Since peeling results in the loss of apples' flavonoids and most of its valuable fiber, choose organically grown apples whenever possible.