Cystic Fibrosis Diet: Food and Nutrition for CF

Medically Reviewed By Jillian Kubala, MS, RD
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Cystic fibrosis (CF) can affect appetite and digestion, often leading to low body weight and nutritional deficiencies. Eating plenty of wholesome foods, like proteins, vegetables, and more, can help you maintain your weight and get the nutrients you need. Read on to learn more about how CF affects the body’s nutritional needs and what people with the condition may want to consider eating.

Sex and gender exist on a spectrum. This article uses the terms “female” and/or “male” to refer to sex that was assigned at birth. 

Learn more about the difference between sex and gender here.

How does cystic fibrosis change your nutritional needs?

Avocado slices and eggs on toast
Sonya Khegay/Stocksy United

It is important for people with CF to eat a diet high in calories, especially calories from protein and fat. Calories are a measure of energy, and people with CF may require twice as much energy as people without the condition to maintain weight and clear recurrent lung infections.

These high nutritional needs are due to the buildup of sticky mucus in the organs, which can affect digestion and influence your appetite.

Common conditions in people with CF that can affect digestion and appetite are discussed below.

Pancreatic insufficiency

Around 85% of people with CF have pancreatic insufficiency, in which enzymes that the pancreas makes don’t reach the intestines. Without these enzymes, the body has a harder time using fat, protein, and carbohydrates.

Pancreatic insufficiency also alters the ability of the pancreas to secrete a natural antacid, make insulin, and send fluid to the intestines to help move food along the gastrointestinal tract.

Delayed stomach emptying

Also called gastroparesis, delayed stomach emptying refers to food exiting the stomach more slowly. This may cause you to feel full for longer than usual, and you may feel the need to eat less often. It can also lead to bloating and nausea, which may reduce your appetite.

Bacterial overgrowth

Your doctors will usually prescribe antibiotics to clear the recurring lung infections that result from CF. However, frequent use of these medications can also kill good bacteria and let bad bacteria grow in the intestine. The imbalance can cause gastric problems, like constipation and bloating.

Learn more about potential complications of CF.

What should people with cystic fibrosis eat?

It’s a good for people with CF to eat plenty of the two essential nutrients that CF strongly affects, which are protein and fat. People need protein to grow and heal. Fats supply energy and help the body process certain nutrients, including vitamins A, D, E, and K.

Many people with CF benefit from working with a nutritionist who can help adjust their diet. They can advise you about eating foods high in the calories and nutrients you need, including:

  • full fat dairy products, like milk, butter, cheese, and yogurt
  • proteins, such as meat, poultry, fish, eggs, and peanut butter
  • carbohydrates, including grains and other starches
  • fruits and vegetables

You may also need to increase your intake of certain minerals, including salt, which is often lost at a higher-than-normal rate through perspiration, and calcium, which can help offset bone weakening due to pancreatic insufficiency.

Nutritionists can also advise you about vitamin supplements containing vitamins A, D, E, and K.

Because CF can make you tired and affect your digestion, it can be hard to eat enough. Your doctor may give you pills with pancreatic enzymes to help you digest food more easily, but paying attention to diet and weight is also critical.

What body mass index should you try to maintain?

There appears to be a correlation between an adequate body mass index (BMI) and better lung function in people with CF. To calculate your BMI, divide your body weight in kilograms by your height in meters squared. The Centers for Disease Control and Prevention (CDC) has a BMI calculator for adults.

According to the Cystic Fibrosis Foundation (CFF), the recommended BMI for females with CF who are more than 20 years old is 22 or above. For males with CF who are more than 20 years old, the recommended BMI is 23 or above.

For people under 21, a recommended BMI is equal to or higher than the 50th percentile listed in the CDC growth chart.

A nutritionist or registered dietitian, along with your doctor, can help you establish a BMI goal. Although most people with CF have higher-than-usual calorie needs, an individualized approach with the help of medical professionals is necessary to avoid overweight and obesity. These conditions may cause complications in people with CF.

What are some meal planning tips for people with cystic fibrosis?

Having a low body weight is common among people with CF, but there are ways to address it.

The CFF notes that good meal planning includes setting aside some time to focus on it, perhaps before you go to sleep. Think about ensuring that food will be available to you the next day, and determine what you may need to pack to take with you if you’re leaving home.

Keep the kitchen organized so you can see what you might be running low on, and stock plenty of high calorie, high fat, and high protein foods. Peanut butter, full fat dairy, nuts, and cheese are all good choices.

Other tips include:

  • Consider making large portions of food so that you can freeze some to have on hand.
  • Try unsaturated fats, like olive or walnut oil, which are healthier than saturated fats.
  • A slow cooker is an easy way to make high protein dishes like hearty stews or braised meats.
  • You can eat microwaveable meals if you are in a rush, like a frozen breakfast sandwich or burrito, so you’re not tempted to skip a meal.

Adding extra calories

If you need to gain weight, a simple guideline is to add an extra 500 calories a day to what you usually eat. Here are some snacks and meals that have about 500 calories, according to the CFF:

  • grilled ham and cheese sandwich with avocado
  • spaghetti with olive oil, sauce, and extra cheese
  • peanut butter and jelly sandwich and a glass of whole milk
  • one cup mixed nuts or trail mix

The CFF also suggests you can get your 500 extra calories by adding 100 calories to three meals and two snacks each day. Here are some 100-calorie options to raise your intake each time you eat:

  • 2 tablespoons chopped nuts
  • 1 tablespoon nut butter
  • 1/2 cup avocado
  • 2 slices crumbled bacon

Balancing your diet

While people with CF can have unlimited fats, you may want to aim for a balanced diet. Along with the high protein and high fat, try to eat plenty of fruits and vegetables for their fiber, vitamin, and mineral contents.

If you find you’re having trouble eating or keeping weight on, your doctor or nutritionist can advise you on how to eat to get the energy you need.


People with CF need to eat a diet high in calories, especially from fat and protein. You can reach your calorie intake goal through meal planning and avoiding skipping meals.

Your care team can guide you on how to eat when you have CF, so you can stay healthier with a high calorie, balanced diet.

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Medical Reviewer: Jillian Kubala, MS, RD
Last Review Date: 2023 Jan 26
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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