Originally cultivated by ancient North Americans, sunflower seeds have been used as everything from a snakebite cure to a snack for baseball players giving up tobacco. The kernels are high in B vitamins and minerals like copper and magnesium. Because they pack a lot of fat and calories into a small space, they have a reputation for being fattening. Eat them in moderation, however, and they can be a healthy part of a balanced diet.
High in Calories
Sunflower seed kernels contain 164 to 175 calories in every ounce, depending on which type you have: dried, oil-roasted, dry-roasted or toasted. For a healthy adult following a 2,000-calorie diet, that amount would fulfill 8.2 to nearly 9 percent of the day's caloric limit. Unless you're careful to control your intake of other foods, regularly eating sunflower seeds could cause you to gain weight. For the lowest-calorie option, choose dried sunflower seed kernels; toasted kernels supply the most calories per ounce.
Rich in Fats
Most of the calories in sunflower seeds are contributed by fat. Each ounce of toasted sunflower seeds has 16 grams of fat, while the other types contain approximately 14 grams. The diet of a healthy adult should consist of 25 to 35 percent fat, and if you consume 2,000 calories a day, 1 ounce of toasted sunflower seeds would supply about 24 percent of your recommended daily fat intake. Although the majority of the fat is heart-healthy polyunsaturated fat, too much means extra calories -- and extra pounds.
Full of Filling Fiber
Although they're high in calories, sunflower seed kernels are also high in fiber. An ounce of the toasted kernels contains 3.3 grams of fiber, supplying nearly 11 percent of the recommended daily intake of fiber for men age 31 to 50 and 13 percent of the requirement for women of the same age. Oil- and dry-roasted sunflower seeds contain around 3 grams of fiber per ounce, and dried kernels have 2.4 grams. An article published in "Nutrition Reviews" in 2001 reported that increasing the fiber in your diet promotes weight loss.
Controlling Portion Size
Portion control is the key to enjoying sunflower seeds without consuming enough extra calories to cause weight gain. Each 1-ounce serving is equivalent to just under one-quarter cup of the kernels without their hulls. Increase that amount to 1/2 cup, and you could take in as much 350 calories and 32 grams of fat in minutes. Measure sunflower seeds carefully before eating, and use them to enhance low-fat meals -- stir them into your oatmeal, sprinkle them on nonfat Greek yogurt or toss them with your salad ingredients.