Diuretic medications are called water pills for a reason: They help your body get rid of excess fluid. “They work by blocking the absorption of sodium, chloride and water from the kidneys, allowing for an increase in urine output,” says cardiologist Patrick Fratellone, MD, of Fratellone Medical Associates in New York City. In other words, diuretics make you urinate a lot, at least for the first 6 hours or so after you take them.

If you’re taking furosemide (Lasix®), that means you probably have high blood pressure (hypertension) and/or a condition that causes swelling in your legs or ankles or fluid buildup in your lungs. The most common culprits of swelling are heart failure, leaky heart valves, kidney disease and liver disease.

Flushing out that extra fluid is important. When your fluid levels are too high, your heart and arteries work harder because there’s more blood and fluid to move around your body. That can leave you at increased risk for stroke, heart failure, kidney failure or heart attack. Furosemide and similar medications can be crucial treatment tools to keep you healthy. (Get a coupon for furosemide now.)

Here’s what else matters when you’re taking a strong diuretic such as furosemide: your diet. The foods you eat can have a direct effect on the amount of fluid your body retains. There are 2 main things to focus on:

  1. Reducing salt. When you consume high-sodium foods or beverages, your kidneys have a harder time removing fluid. That fluid then builds up in your body, raising your blood pressure. That’s the exact opposite of what needs to happen, says Carmen Roberts, RD, a clinical dietitian specialist with Johns Hopkins Bayview Medical Center in Baltimore. “While it helps to skip the salt shaker at the table, most of the sodium in the American diet (almost 80%) comes from processed and packaged foods. These foods can be high in sodium even if they don’t taste salty,” she says. Your daily sodium intake while you’re taking a diuretic should be about 1,500 mg or less, says Roberts.
  2. Monitoring potassium. The main job of a diuretic is to cause fluid loss. But the downside is that electrolytes such as potassium can be depleted, too. That’s why it’s important to watch your potassium levels and make sure you’re getting enough, says Roberts. “Low potassium can cause muscle weakness, cramping and even irregular heartbeat,” she says.

The general guideline for potassium intake is about 4,000 mg a day, says Roberts. Everyone’s needs vary though. Your doctor can help you figure out what to aim for. (Do you think high blood pressure is inevitable as you age? We’ve got the surprising answers here.)

If you’re taking furosemide or a similar diuretic, here are some tips on what to skip and what to stock up on.

The diuretic diet: foods to avoid

  • Frozen dinners. Yes, they’re easy and convenient. “But most frozen meals, even the lower-calorie ones, contain close to 1,000 mg sodium each,” says Roberts. “Look for frozen entrees labeled ‘light’ or ‘lower sodium,’” Roberts says. Some brands to look for: Amy’s vegetarian meals, Healthy Choice and some Smart Ones entrees. And always check the nutrition label. You’ll want to choose meals with a sodium content of 500 mg or less.
  • Canned or pickled foods. We’re looking at you, dill pickles. Of course they’re delicious, but canned or jarred pickles (and other pickled foods) can be high in sodium. Look for reduced-sodium or no-salt-added products instead, Roberts says.
  • Snack foods. Who isn’t reaching for chips, pretzels and crackers during these long days of social isolation? “Packaged snacks have salt added as a preservative,” Roberts says. If you’re craving something crunchy, grab raw veggies or unsalted popcorn, pretzels or unsalted nuts.
  • Deli meats. These are seriously sneaky salty saboteurs. “One slice of lunch meat can have more than 300 mg sodium,” Roberts says. At the deli counter, ask for no- or low-salt varieties. These can contain significantly less sodium, she says. Better yet, roast your own turkey breast and use that on your sandwich, Roberts suggests.
  • Cheese. Processed cheese is chock-full of sodium. “One slice of American cheese has more than 400 mg sodium. Instead, choose fresh mozzarella at 175 mg sodium per ounce, or Swiss, which comes in under 60 mg per ounce,” Roberts says.
  • Condiments, sauces and dressings. You don’t need to eat totally naked food, but be aware that many condiments have sodium. A tablespoon of mayo has 100 mg sodium, but you can swap in creamy, spreadable Greek yogurt, at just 10 mg.

“You can experiment with making your own condiments and dressings to control the amount of added salt,” Roberts says. “Try low-sodium seasoning alternatives, such as salt-free seasoning blends. Mrs. Dash and McCormick make some great ones. Other choices include lemon, ginger, curry, onion, garlic, dry mustard and dried herbs such as bay leaves, basil and rosemary,” she says.

Breads and cereals. This category may not be the first thing that comes to mind when you think of salty foods, but don’t be deceived. Checking labels is essential. For example, 1 cup of Grape-Nuts cereal has 560 mg sodium, while a serving of Kellogg’s Unfrosted Mini-Wheats has 0 mg. “And here’s another reason to choose whole grains: Two slices of white bread contain 280 mg sodium, versus as little as 6 mg for the same amount of whole-grain bread,” Roberts says.

Soda (including diet soda). Diet ginger ale contains about 85 mg sodium per can. (Who knew this was a suspiciously salty beverage?) “While this is not a lot, if you drink several sodas a day, it can really add up,” Roberts says.

Diuretic diet: foods to stock up on

  • Potassium-rich foods. The good news? You have tons of fruits and vegetables to choose from: avocados, bananas, beans, leafy greens, potatoes and more. Yogurt, chicken and salmon are good sources, too, according to Harvard Medical School.
  • Everything in the DASH plan. If you have high blood pressure, the DASH diet (Dietary Approaches to Stop Hypertension) is a great one to follow, Roberts says. “Because this diet is low in sodium, it prevents water retention that can raise blood pressure,” she says. “Research has shown that this diet can lower your blood pressure in as little as 2 weeks. Over time, your systolic blood pressure (the top number) can drop by as much as 14 points.”

Bonus: The DASH diet offers loads of additional health benefits including prevention of osteoporosis, cancer, heart disease, stroke and diabetes, Roberts says. DASH includes:

  • Moderate amounts of whole grains
  • Fish
  • Poultry
  • Nuts
  • Vegetables
  • Fruits
  • Low-fat dairy products

If you need help getting started on DASH, talk with your health care provider or dietitian. You can also check out this guide from the National Heart, Lung, and Blood Institute.

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