The typical American diet doesn't contain the recommended amount of potassium, according to Colorado State University Extension. Getting plenty of potassium in your diet will help you keep your blood pressure levels under control, and your nerves and muscles functioning properly. It can be especially difficult to meet the recommended potassium intake if you are on a low-calorie diet. There aren't a lot of low-calorie foods high in potassium -- meaning those foods that contain at least 20 percent of the daily value for potassium per serving that are also low in calories.

Less Than 40 Calories a Serving

The Food and Drug Administration defines a low-calorie food as one that contains less than 40 calories per serving. High-potassium foods that fit this definition include cooked amaranth leaves, cardoon, cooked Swiss chard and cooked beet greens. You can steam or saute amaranth leaves or add them to soups or other dishes, just as you would other green leafy vegetables. Cardoon is similar to a globe artichoke and can be eaten raw in salads or you can cook the leaves and stalks together as a side dish or part of a main dish.

Less Than 75 Calories a Serving

Other relatively low-calorie options for foods high in potassium include bamboo shoots, cooked spinach, taro root and tomato sauce. Be sure to thoroughly cook taro root, or it could cause your mouth to itch because of the calcium oxalate it contains. A mix of chicken, spinach or other green leafy vegetable, plus tomato, onion, coconut cream and lemon juice makes a delicious, potassium-rich meal.

Less Than 125 Calories a Serving

Dishcloth gourd, Hubbard squash and acorn squash are also high in potassium and somewhat low in calories. Dishcloth gourd is also called luffa or vegetable sponge and can be substituted for zucchini or squash in recipes. You can also cook these gourds and stuff them or use sliced dishcloth gourd in place of eggplant in eggplant parmigiana, notes the "Mother Earth News" website 4.

Canned Soup Considerations

Check the labels of your favorite canned soups. Some canned soups are both low in calories and high in potassium. Unfortunately, canned soups are also one of the foods that contribute high levels of sodium to the typical American diet, so these may not be the best way to increase your potassium intake, because you'll need the potassium in the soup to help counteract the blood-pressure raising effects of the sodium it contains.