What to Eat When You Have Cystic Fibrosis

Dietary Recommendations for Better Management

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A healthy diet for cystic fibrosis (CF) addresses the primary challenge of the disease—to provide ample macronutrients (such as fats, proteins, and carbohydrates) for normal weight maintenance, growth, and development.

Cystic fibrosis is a genetic disorder that results in the body making thick mucus. This mucus accumulation can prevent the small intestine from absorbing vital nutrients, including fats and vitamins. The disease may also interfere with the normal function of the pancreas, inhibiting enzymes needed to break down food.

Therefore, the overall goal of the cystic fibrosis diet is to eat enough nutrient-dense food and take supplements to compensate for the body’s absorption and metabolism problems.

Understanding Cystic Fibrosis

Verywell / Emily Roberts


People with CF—particularly children and teenagers—must eat extra calories and nutrients to help them gain weight adequately, as well as enabling a strong immune system (to fight off infection). Colds and flu are common in those with CF because the lungs also have an abnormal accumulation of mucus.

The increase in mucus production in the pancreas may interfere with the body’s normal production and transport of pancreatic enzymes. In fact, nearly 90% of those with CF are unable to pass pancreatic enzymes which are required to digest fat, protein, and starch in the body.

The benefits of eating a cystic fibrosis diet include:

  • Improvement in energy level
  • Boost to the immune system
  • Adequate weight maintenance
  • Adequate growth and development (in kids and teenagers)
  • Ample availability of pancreatic enzymes for normal nutrient metabolism

Medical Research

The preferred diet for cystic fibrosis is one involving unlimited amounts of nutrient-dense foods. In a study published in the American Journal of Diseases in Children, participants—ranging in age from 2 to 27— who ate a non-restricted fat diet, for a period of four years, were found to:

  • Significantly increase the average energy intake to over 120%
  • Gain a considerable amount of weight
  • Experience stabilization of pulmonary (lung) function
  • Maintain established weight and height scores during adolescence

Enzymes were given to the study participants to control steatorrhea (the excretion of abnormal quantities of fat in the feces, due to a reduced ability to absorb fat in the intestine).

Diet for infants with cystic fibrosis: A 2012 study reported that breast milk is the preferred diet for infants with cystic fibrosis during the first year of life. A study conducted in Italy found that breastfeeding improved lung function and lowered the incidence of infection during the first three years of life.

How It Works

According to the Cystic Fibrosis Foundation, the caloric guidelines for the cystic fibrosis diet should include:

  • 2500 calories per day for women to maintain weight and 3,000 calories per day for those who need to gain weight
  • 3,000 calories per day for men who aim to maintain their current weight and 3,700 calories per day to gain weight
  • An additional 300 calories or more per day for women with cystic fibrosis who become pregnant
  • 3,000 to 5,000 calories per day for adolescents

The calorie requirement for infants and children changes according to age as well as the stages of growth and development. The pediatrician or other healthcare provider can provide a recommendation for caloric intake for children based on these and other factors.

The easiest way to increase the number of calories in any meal is to increase the fat content. Healthy fats include oil (such as avocado and olive oil), nuts, salmon (and other fatty fish), nut butter, and more.

Those with CF need to be sure to take adequate amounts of pancreatic enzymes to digest fats, as prescribed by the healthcare provider. They must also eat enough fat in their diet to metabolize the fat-soluble vitamins (such as vitamins A, D, E, and K).


The cystic fibrosis diet should be followed throughout a person’s entire lifetime. But the nutritional needs (such as the number of calories needed per day) change as a person ages, and during certain life events like during adolescence or pregnancy.

What to Eat

The cystic fibrosis diet is a guideline on how to get enough nutrition, rather than a diet that involves restricting foods. In general, the cystic fibrosis diet involves foods that are high in nutritional value that will add calories from the macronutrients (fats, carbohydrates and proteins).

Compliant Foods
  • Fruits and vegetables

  • Fatty fish

  • Avocados

  • Whole milk products

  • Nuts

  • Olives

Non-Compliant Foods
  • Trans fats

  • Foods with empty calories, such as sugared sodas

  • Low-fat products, such as low-fat salad dressings

 Here are some examples of foods that are recommended.

  • High-calorie snacks: Such as an English muffin with peanut butter or a bagel with cream cheese, whole milk yogurt or cottage cheese, eggs with cheese and butter, ice cream, nuts, nut butter, trail mix, milkshakes and high-calorie smoothies
  • High-calorie breakfasts: Including sausage or bacon and eggs, toast with cream cheese or butter, pancakes with maple syrup and butter, cereal with whole milk, and more
  • High-calorie lunches: Such as pasta salads with healthy mayo (like olive oil or avocado-based mayo), peanut butter and jelly sandwiches, tuna sandwiches (with plenty of healthy mayo) and creamed soups
  • High-calorie dinners: Like steak and baked potatoes, fried foods in healthy cooking oil (such as avocado oil), vegetables with ample amounts of butter, multi-grain or whole grain bread and butter, pizza with extra cheese and more
  • High-calorie bedtime snacks and desserts: Including ice cream sundaes with whipped cream, nuts, fruit, and other toppings, a bowl of granola with nuts and half-and-half (instead of milk), a homemade milkshake or smoothie (with flax, chia, or other seeds, high protein shake mix, fruit and more)

Foods that help to boost calories include heavy cream, butter, maple syrup, chopped nuts, powdered milk, and chocolate syrup.

It’s important for those with CF to get enough protein in the diet, in fact, approximately 20% of the total calories a person with CF (particularly those who are growing) eats should come from protein sources such as meat, eggs, fish, nuts, beans and legumes and soy.


Those with CF who have pancreatic insufficiency may be prescribed enzymes to take with each meal or snack. The enzymes are necessary to properly break down and digest the food, enabling normal growth and development in kids and teenagers and maintaining weight for anyone with CF.

Usually the healthcare provider collaborates with the dietician to ensure the right dosage of pancreatic enzymes. Pancreatic enzymes should never be crushed up or chewed, but rather, they should be swallowed whole.

Recommended Timing

The cystic fibrosis diet involves as many meals and snacks as a person can eat, to attain the desired caloric intake and other nutrients needed each day. Under most circumstances, a person with cystic fibrosis is not limited to the number of meals or snacks eaten. In general three meals and at least two or three high-calorie, high-fat meals and snacks should be spread out throughout the day.

Cooking Tips

Many people are on the go these days, which may present a challenge when attempting to eat enough of the foods required on the cystic fibrosis diet. The Cystic Fibrosis Foundation provides tips on grab-and-go foods, these include:

  • Use a tortilla wrap to wrap up scrambled eggs with cheese and bacon (add butter for a calorie boost).
  • Microwave a breakfast sandwich to eat on the run.
  • Keep high-calorie supplemental shakes (canned) available.
  • Prepare a high-calorie shake (such as one with nut butter, fruit and protein powder) and keep it in the refrigerator, ready to be blended in the morning with breakfast.
  • Make ahead batches of pancakes or French toast and freeze, pop them in the toaster and serve with cashew or peanut butter, butter, maple syrup, fruit toppings and whipped cream in the morning.
  • Have packets of single serving oatmeal available, add hot cream, and take it in a to-go cup.
  • Take along cold cereal in individual boxes, pour into a Styrofoam or plastic bowl, and serve with boxed whole milk (that does not need to be refrigerated).
  • Keep fresh fruit in handy places (such as a purse, briefcase, and in a bowl next to the door to grab as you go).
  • Keep bagels, Italian sauce in a jar, shredded cheese, and pepperoni in the office or backpack for a ready-made pizza snack.
  • Make peanut butter and jelly sandwiches or turkey, ham, and cheese sandwiches in advance, freeze them, then throw one in a backpack or briefcase to thaw, ready to eat for a quick snack or meal.
  • Keep ready-made microwavable burritos handy, heat, place in foil and take them on the run.
  • Pack a tuna kit (with tuna, crackers, and mayo) instant soup or microwavable meals—such as meatballs, mac and cheese, and more—for quick on-the-go nutrition.

When frying foods to increase the caloric value, keep in mind that some types of oil (such as olive oil) easily become denatured, breaking down at high temperatures. Avocado oil and coconut oil are preferable for frying foods at high temperatures. Olive oil is best eaten uncooked (as oil in salad dressing or dipping oil) or used for low temperature sautéing.


Salt is an important nutrient for those with CF. Salt is necessary for various bodily functions—such as muscle function, nerve cell transmission, and digestion. People with CF have a higher than normal concentration of salt in their sweat. This results in the need to replace the salt that is lost, particularly on a hot day, or when working out and sweating a lot.

Eating a healthy, salty snack, such as salted nuts, can help replace the salt. Those who work out regularly should consult with a dietitian to get a recommendation on a sports drink (with ample sodium) to drink after a workout or when being outside in hot weather.

Vegetarian Diet

Some people with CF have managed to eat a vegetarian diet that provides the necessary calories and nutrients. Here are some tips from the Cystic Fibrosis Foundation on going meatless:

  • Replace daily dairy servings (on the MyPlate model) with soy, almond milk, or hemp milk, yogurt, or other products.
  • Eat three meals and three snacks every day, do not skip any meals or snacks.
  • Prepare meals the night before.
  • Pack easy to store snacks (such as vegetarian protein bars, nuts, seeds, or nut butters).
  • Focus on getting enough vitamin B12, omega-3 fatty acids (such as from salmon and other wild-caught cold water fish) calcium (from whole fat yogurt, whole milk, and other milk products), iron (from red meat and some green leafy vegetables such as spinach) and zinc (from meat, shellfish, legumes, and nuts such as Brazil nuts).
  • Before going vegetarian, be sure to discuss the diet plan with the dietitian to be sure that the vegetarian cystic fibrosis diet offers enough foods with the necessary nutrients.
  • When ill or when the appetite is not very good, drink high-calorie vegan smoothies or vegan nutritional supplement shakes.

Vegetarian foods recommended for the cystic fibrosis diet include:

  • Whole grain or multi-grain bread with 3 tablespoons peanut butter and banana slices
  • Carrots and whole-grain pita bread with guacamole, black bean dip, or hummus
  • Whole milk yogurt with cashews or almonds
  • Whole milk (full fat) cheese on crackers
  • Protein bar (with at least 10 grams of protein)
  • Fruit smoothie with 3 tablespoons nut butter and chia or flax seeds


The most challenging aspect of the cystic fibrosis diet may be the ability to eat enough calories and nutrients each day. This is true particularly when a person is ill or has a poor appetite. Getting creative by substituting high calorie shakes and smoothies (as well as energy dense commercial supplement drinks) can help fill in the gaps.

Unlike those who don’t suffer from a lifelong illness—such as cystic fibrosis—many people with CF find themselves wishing they could simply skip a meal. It’s an ongoing challenge, particularly for kids and adolescents who are growing. In some situations, tube feedings may be necessary to ensure adequate nutrition.  

Dietary Restrictions

The primary restrictions in the CF diet include foods that are low in fat, such as low-fat milk or low-fat salad dressing. This is because the low-fat option replaces the foods that are more nutrient-dense (in fat, protein, and carbohydrate), which are required.

As with any diet, eating foods with empty calories (such as sugar-laden drinks) is not recommended on the cystic fibrosis diet. People with CF need to eat a balanced diet with a variety of bright-colored fruits and vegetables, whole grains, whole-fat dairy products, and healthy protein.

In addition, people with CF have some specific nutritional needs to help them stay healthy. Getting enough nutrients—such as protein and minerals (like iron and zinc) —to help fight infection, and calcium (to prevent the high risk that people with CF have of getting osteoporosis) is vital to long-term health.

Therefore, the ability to eat enough nutrient-dense foods depends partially on restricting those foods that do not provide the much-needed healthy fats, proteins, and carbohydrates.

CF-Related Diabetes

It’s important to note that some people with CF have a type of diabetes that is related to cystic fibrosis. This type of diabetes is different than other types (such as type 2 diabetes).

Diabetes often occurs in those with CF as a result of mucus obstructing the pancreatic ducts. This prevents insulin from being properly secreted, which results in high blood sugar. Cystic fibrosis-related diabetes is more common as a person ages. Any person over the age of 6 with CF should be tested regularly for diabetes.

When the blood sugar is high, it’s vital to consult with a diabetes specialist regarding dietary recommendations and any other treatment (such as anti-diabetic medications).

A Word From Verywell

Although eating the cystic fibrosis diet every day can present a challenge, it is not insurmountable. There are many online resources designed to give people with CF tips on how to prepare, package, and eat the amount and type of foods that are recommended on the diet.

Just as with any other type of diet, it’s always a good idea to seek out support from others who are going through similar circumstances. For more information on support and treatment for those with cystic fibrosis, access a Cystic Fibrosis Foundation chapter in your local area.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Reed M. Cystic fibrosis: Diet and nutrition. KidsHealth for Teens.

  2. Luder E, Kattan M, Thornton JC, Koehler KM, Bonforte RJ. Efficacy of a nonrestricted fat diet in patients with cystic fibrosis. Am J Dis Child. 1989;143(4):458-64. doi:10.1001/archpedi.1989.02150160084017

  3. Kalnins D, Wilschanski M. Maintenance of nutritional status in patients with cystic fibrosis: New and emerging therapies. Drug Des Devel Ther. 2012;6:151-61. doi:10.2147/DDDT.S9258

  4. Cystic Fibrosis Foundation. Healthy high-calorie eating.

  5. Cystic Fibrosis Foundation. Cystic fibrosis and the vegetarian diet.

By Sherry Christiansen
Sherry Christiansen is a medical writer with a healthcare background. She has worked in the hospital setting and collaborated on Alzheimer's research.