Healthy fats vs. unhealthy fats:

What do people with cystic fibrosis (CF) need to know?

Lara Mathers

CF Dietitian,
BSc (Nutrition & Dietetics, Hon I)

Tamarah Katz

CF Dietitian,
BNutrSc, MNutrDiet


A high fat diet (along with enzyme therapy) became an important part of CF care in the 1980s. Fat is a concentrated source of energy, providing more than double the calories or kilojoules of protein and carbohydrate and therefore allowed people with CF to meet their elevated energy needs more easily.

Energy requirements for people with CF have traditionally been high due to a range of factors including recurrent lung infections, increased work of breathing and malabsorption due to pancreatic insufficiency.1

However not all fats are created equal, some are healthy in that they reduce your risk of cardiovascular disease and are a source of essential fatty acids, and others are unhealthy in that they are associated with an increased risk of cardiovascular disease2, possibly associated with certain cancers3 and have more recently been shown to contribute to an unfavourable gut microbiome.4 As people with CF are living longer it has become increasingly important that the CF diet evolves to promote healthy fats and minimise unhealthy fats.

What is ‘healthy’ fat versus ‘unhealthy’ fat?

Foods like oil, margarine, butter, cream, dairy products, oily fish, meat, nuts and seeds, processed foods and takeaway are all major sources of dietary fat.1

There are four main types of fats:5

Healthy Unhealthy
(this includes EFA’s or essential fatty acids)
14_fish.png Saturated^ 43_meat.png ^Dairy foods contain saturated fat but do not need to be limited as they are protective for heart health 31_yogurt.png
Monounsaturated 30_oil.png Trans fats 42_junk_food.png

Polyunsaturated and monounsaturated fats are considered ‘healthy’ fats as they are not associated with an increase in cholesterol or cardiovascular risk.5 Foods containing these fats should be included in your diet every day.

Saturated and trans fats are ‘unhealthy’ fats as they have been shown to increase LDL cholesterol (unhealthy cholesterol) and increase cardiac risk in the general adult population.5 Foods containing these fats should be eaten in limited quantities. However, dairy foods like cheese, milk and yoghurt are sources of saturated fat but do not need to be limited.

Examples of different sources of dietary fat5

Polyunsaturated fats

(including essential fatty acids)

Monounsaturated fats


Saturated fats


Trans fats


Have often Have often Have often Limit Limit

Fatty fish (such as salmon, tuna, herring, mackerel and sardines)

Avocado, olives Dairy made from whole-milk such as yoghurt and cheese* Visible fat on meat such as beef, veal, lamb, pork, poultry Commercially baked products (e.g. biscuits, croissants, pastries, doughnuts)
Sunflower, safflower and canola oil Olive oil, peanut oil, canola oil   Butter Deep fried takeaway foods e.g. hot chips, hamburgers, chicken nuggets, battered fish
Some nuts (such as walnuts, pine nuts, brazil nuts, pecans) Natural peanut butter   Cream, ice-cream Vegetable shortening
Tahini (sesame seed spread) Some nuts (such as almonds, cashews, peanuts, hazelnuts)   Coconut oil and cocoa butter  
Seeds (such as linseed, pepitas, sunflower and chia seeds)        

*Importantly, although whole-milk dairy products like full-fat yoghurt and cheese are sources of saturated fat, evidence
now suggests that dairy products appear to have a protective effect on some cardiovascular risk factors compared to
other animal sources of saturated fat.6,7 Therefore these should be included in your diet every day.

How much fat is needed?

The amount of fat you need should be personalised based on your current weight gain needs, one size does not fit all. Some individuals with CF may have very high energy needs, requiring a high fat diet or 35–40% of their daily energy needs coming from fat.1,8 However an increasing proportion of people with CF are now  above a healthy weight range, and it may be more appropriate for those to follow the general population guidelines of 30% of their daily energy needs as fat.

This article provides a general overview of nutritional goals in people with CF. Your CF care team, including your dietitian, can provide you with more detailed information on your specific dietary requirements.

    1. Saxby N et al and the Australian and New Zealand Cystic Fibrosis Nutrition Guideline Authorship Group (2017). Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand, ed. Scott C. Bell, Thoracic Society of Australia and New Zealand, Sydney.

    2. Bojková B, Winklewski PJ, Wszedybyl-Winklewska M. Dietary Fat and Cancer-Which Is Good, Which Is Bad, and the Body of Evidence. Int J Mol Sci. 2020 Jun 9;21(11):4114. doi: 10.3390/ijms21114114. PMID: 32526973; PMCID: PMC7312362. Cancer Council.

    3. Coffey MJ, McKay IR, Doumit M, et al. Evaluating the Alimentary and Respiratory Tracts in Health and disease (EARTH) research programme: a protocol for prospective, longitudinal, controlled, observational studies in children with chronic disease at an Australian tertiary paediatric hospital BMJ Open 2020;10:e033916.

    4. Cystic Fibrosis Australia. Cystic Fibrosis in Australia 2014: 17th Annual Report from the Australian Cystic Fibrosis Data Registry. August 2016.

    5. Duarte C, Boccardi V, Amaro Andrade P, Souza Lopes AC, Jacques PF. Dairy versus other saturated fats source
      and cardiometabolic risk markers: Systematic review of randomized controlled trials. Crit Rev Food Sci Nutr. 2021;61(3):450-461.

    6. Javier Fontecha, Maria Visitación Calvo, Manuela Juarez, Angel Gil, Vicente Martínez-Vizcaino, Milk and Dairy Product Consumption and Cardiovascular Diseases: An Overview of Systematic Reviews and Meta-Analyses, Advances in Nutrition, Volume 10, Issue suppl_2, May 2019, Pages S164–S189 

    7. Cystic Fibrosis Australia. Nutrition & Cystic Fibrosis - A Guide for Adults. Published 2016.

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