# Nutrition and diets in cystic fibrosis
Nutrition plays an important role in cystic fibrosis, because the disease makes it difficult for the body to absorb nutrients and maintain a healthy weight. This tab describes which dietary patterns and diets are used or studied in cystic fibrosis, and what research shows about them.
Protein-rich nutrition
ProveniIncluded in official guidelines, or approved by EMA or FDA
High-protein nutrition consists of eating more foods with lots of protein, such as meat, fish, eggs, dairy products and legumes.
In cystic fibrosis, a lot of energy is used for breathing and digestion works more slowly. Therefore, people with this disease generally need more calories and more protein than people without cystic fibrosis. Research shows that adequate protein intake helps maintain muscle mass and prevent being underweight. This is especially important in children, as they are growing, and in adults who want to feel stronger. Traditionally, emphasis was always placed on how much someone should eat; newer research (2026) shows that this focus on nutrition is changing now that better medicines are available, but protein intake remains important.
Interaction with treatment: Some medicines (such as certain antibiotics and supportive agents) can affect appetite and digestion, which deserves discussion with your healthcare provider.
High-calorie nutrition
ProveniIncluded in official guidelines, or approved by EMA or FDA
High-calorie nutrition contains a lot of energy per amount of food, through the use of fats and carbohydrates. These can be foods such as nuts, oil, full-fat dairy products and energy-rich drinks.
Because digestion is reduced in cystic fibrosis, the body absorbs fewer calories from food. Therefore, many people with cystic fibrosis are advised to get enough calories so they can maintain or reach their weight. This also helps maintain better resistance to infections.
Risks: In people with cystic fibrosis, excessive fatty food can sometimes cause abdominal complaints, because the pancreatic enzyme pancreatin (which is usually added) cannot cope with everything. These go together: the amount of fat and the dosage of supportive agents are adjusted to each other.
Vitamin contribution from food
ProveniIncluded in official guidelines, or approved by EMA or FDA
This is about adequate intake of vitamins A, D, E and K, which the body must obtain from food. These vitamins are mainly found in fats, vegetables and certain dairy products.
In cystic fibrosis, these fat-soluble vitamins are poorly absorbed, because the pancreatic enzyme does not work well. Therefore, many people with cystic fibrosis are prescribed vitamin pills. But food containing these vitamins remains important, because food supplies them more naturally. Research supports that adequate vitamin intake helps fight inflammation and keep bones stronger.
Interaction with treatment: Vitamin contribution should be adjusted to the extent to which someone uses pancreatic enzyme and how well the body absorbs the vitamins.
Salt balance and electrolytes from food
ResearchediPositive results in clinical studies, not yet standard treatment
This is about getting enough salt and electrolytes (such as sodium and chloride) from food, for example through bread, cheese, vegetables and liquid food.
In cystic fibrosis, the body loses a lot of salt through sweat. This happens especially during exercise or warm weather. New research (2026) has shown that the CFTR defect (the genetic defect behind cystic fibrosis) affects the salt balance throughout the body, also in organs other than lungs and digestion. This makes the role of adequate salt intake better understood. Many people with cystic fibrosis therefore prefer saltier food or receive extra salt supplements.
Risks: Too little salt can cause fatigue and weakness. Too much salt can (especially in the long term) affect blood pressure, which should be discussed with your healthcare provider.
Nutrition and digestive problems
ResearchediPositive results in clinical studies, not yet standard treatment
This is about dietary choices that help support digestion, especially in combination with pancreatic enzyme (pancreatin). Such as eating regular meals, not eating too large portions at once, and avoiding food that contains a lot of rough fiber or is difficult to digest.
Research shows that regularity in eating and timing of pancreatic enzyme work better than random food intake. A pubmed article (2026) has also been published about Helicobacter pylori (a bacterium in the stomach) in children with cystic fibrosis, which examines how infections affect digestion. This suggests that dietary choices and stomach protection sometimes need to be considered together.
Risks: Too little food with rough fiber can cause constipation; too much can worsen diarrhea. This should be aligned with how well the pancreatic enzyme works and what the individual stomach can handle.
Periodic fasting or intermittent fasting
UnproveniNo scientific evidence that it works
This means not eating for certain periods (for example, fasting 16 hours a day, or eating less for a few days a week) or only consuming food during certain hours.
Little research has been done on periodic fasting in cystic fibrosis. Because people with cystic fibrosis already struggle with calorie intake and weight maintenance, this pattern is usually not encouraged. However, doctors and dietitians regularly examine whether traditional, strict feeding schedules (such as strict meal regularity) are still necessary now that better medicines are available — this is the subject of recent studies (2026).
Mediterranean dietary pattern
ResearchediPositive results in clinical studies, not yet standard treatment
This pattern consists of lots of vegetables, fruit, grains, nuts, olive oil, fish and little red meat.
Specific research on the Mediterranean pattern for cystic fibrosis has been limited. However, we know that this pattern has anti-inflammatory effects, which could be beneficial because cystic fibrosis is accompanied by chronic lung inflammation. For adults with cystic fibrosis, this pattern could therefore have benefits, for example through the olive oil (easy digestibility) and fish variety (seafood contains a lot of omega-3). However, this should be introduced cautiously, because the calories in this pattern are not always high enough for people who need many calories.
Ketogenic diet
Advised againstiProven ineffective or harmful, or dangerous in combination with your treatment
A ketogenic diet strictly limits carbohydrates and greatly increases fats and proteins.
This diet is discouraged in cystic fibrosis. The reason: people with cystic fibrosis already struggle to absorb their calories and nutrients properly, and ketogenic eating is difficult for them. Also, the body becomes exhausted more quickly from it. Furthermore, it can cause gallstones and kidney disease, which are risks that people with cystic fibrosis already face. The diet does not align with the medical goals of treatment.
Nutrition and new medicines
ResearchediPositive results in clinical studies, not yet standard treatment
This is about how dietary choices can change now that better medicines (CFTR modulators) are available. These medicines help the CFTR protein work better, so digestion can improve.
Recent research (2026) shows that people with cystic fibrosis and their healthcare providers are reassessing their views on nutrition, now that the disease can be better controlled. Where every calorie once counted, some people now have more flexibility. At the same time, nutrition remains important, but the focus may be shifting from pure calorie intake to nutritional quality and wellbeing. This research is ongoing, and for now it is still unclear exactly how this will turn out. It does emphasize that nutrition is not a fixed schedule, but evolves with treatment.
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Dietary choices in cystic fibrosis are completely tailored. They depend on how well someone's pancreatic function is, what medicines they take, how their weight is, and what their stomach tolerates well. This makes working with a dietitian who has experience with cystic fibrosis essential. Changes in nutrition should always be discussed and adapted to the individual situation and treatment plan.
_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._