Low-Sugar High-Fat Diet for Cystic Fibrosis

(FEED-CF Trial)

Overseen By Swati Zaveri, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Emory University

Must not be taking: Steroids

Disqualifiers: CFRD, Pregnancy, Lactation, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 7

Duration: 8 weeks

60 Participants Needed

Trial Summary

What is the purpose of this trial?

This trial will test if a low-sugar diet can reduce diabetes risk and organ fat in adults with cystic fibrosis. Participants will follow either a low-sugar, high-fat diet or their usual CF diet for a few months. The goal is to see if cutting down on sugar improves health outcomes.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but it does require that your medical regimen, including medications, has not changed for at least 21 days before the study. This suggests that you should not make changes to your medications right before or during the trial.

What data supports the effectiveness of the Low-Sugar High-Fat Diet treatment for Cystic Fibrosis?

Research suggests that high-fat diets can lead to increased body fat, which might be beneficial for individuals with Cystic Fibrosis who often struggle to maintain a healthy weight. Additionally, reducing added sugars can improve overall diet quality, which may support better health outcomes. ^{1 2 3 4 5}

Is a low-sugar high-fat diet generally safe for humans?

Research suggests that high-fat diets are associated with obesity, but there is no clear evidence that normal levels of added sugars in the diet uniquely increase the risk of obesity, diabetes, or heart disease. However, the combination of high sugar and high fat may promote obesity and metabolic issues, so caution is advised. ^{4 6 7 8 9}

How does the low-sugar high-fat diet treatment for cystic fibrosis differ from other treatments?

This treatment is unique because it focuses on reducing added sugars while maintaining a high-fat intake, which is different from typical dietary advice that often restricts both sugar and fat. This approach may help manage energy intake and nutritional needs specific to cystic fibrosis, where maintaining a high-calorie diet is crucial. ^{4 10 11 12 13}

Research Team

Jessica A Alvarez, PhD, RD

Principal Investigator

Emory University

Eligibility Criteria

Adults over 18 with confirmed cystic fibrosis, who consume more than 16 teaspoons of added sugar daily and have exocrine pancreatic insufficiency can join. Those with CFRD, recent CFTR modulator use, organ transplant waiting list status, life expectancy under a year, uncontrolled conditions or dietary restrictions that conflict with the study's menu are excluded.

Inclusion Criteria

I have been diagnosed with cystic fibrosis based on sweat test or genetic testing.

My pancreas does not produce enough digestive enzymes.

Your daily added sugar intake is more than 16 teaspoons, as calculated from a questionnaire or food record.

Exclusion Criteria

Current pregnancy or lactation or plans to become pregnant during study period

Any food allergies or intolerances that cannot be accommodated

Actively trying to gain or lose weight (May re-screen at a later date)

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1 visit

1 visit (in-person)

Baseline

Baseline visit for an insulin secretion test and MRI testing to measure visceral fat

1 visit

1 visit (in-person)

Treatment

Participants receive either a low-added sugar, high-fat diet or a typical CF diet for 8 weeks

8 weeks

Food delivered every 3-4 days

Midpoint Check-in

4-week visit for an oral glucose tolerance test and in-person check-in

1 visit

1 visit (in-person)

Follow-up

8-week visit for another GPA and MRI to assess changes in risk markers for diabetes and visceral fat

1 visit

1 visit (in-person)

Treatment Details

Interventions

• High-added sugar, high-fat CF diet
• Low-added sugar, high-fat diet

Trial Overview The FEED-CF trial is testing how diet affects diabetes risk in cystic fibrosis patients by comparing two diets: one low in added sugars but high in fats versus the standard high-sugar, high-fat CF diet. Participants will be randomly assigned to one of these diets for 8 weeks.

Participant Groups

Group I: Low-added sugar, high-fat diet Arm Experimental Treatment 1 Intervention

Patients will receive a low-added sugar, high-fat diet for 8 weeks. Study menus will be designed by registered dietitians using the Nutrient Database System for Research (NDSR) software program with a 2-wk rotation.Total kcal provided will be individually tailored to maintain body weight and adjusted throughout as needed. All foods (including snacks and drinks) for 8 wks will be delivered to participants' homes. Menus will be designed so that food will be delivered to subjects' homes every 3-4 days. It will be expected that participants consume only the foods provided by the study.

Group II: Typical CF diet Arm Active Control 1 Intervention

Patients will receive a high-added sugar, high-fat CF diet for 8 weeks. Study menus will be designed by registered dietitians using the Nutrient Database System for Research (NDSR) software program with a 2-wk rotation. Total kcal provided will be individually tailored to maintain body weight and adjusted throughout as needed. All foods (including snacks and drinks) for 8 wks will be delivered to participants' homes. Menus will be designed so that food will be delivered to subjects' homes every 3-4 days. It will be expected that participants consume only the foods provided by the study.

Who Is Running the Clinical Trial?

Emory University

Lead Sponsor

Trials

1,735

Recruited

2,605,000+

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Collaborator

Trials

2,513

Recruited

4,366,000+

Findings from Research

Intake of saturated trans fatty acids and refined carbohydrates, especially sugar, is linked to higher risks of obesity, diabetes, and cardiovascular disease (CVD), highlighting the importance of dietary guidelines that limit these components.

A recent randomized controlled trial demonstrated that adhering to current dietary guidelines can positively impact cardiovascular risk and nutrient intake compared to a traditional UK diet, supporting the need for balanced macronutrient consumption.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

How important is the relative balance of fat and carbohydrate as sources of energy in relation to health? Sanders, TA.[2022]

In a study of 169 participants on a hypocaloric, low-fat diet, significant reductions in high-fat and high-added-sugar food groups were observed over 6 months, indicating effective dietary changes.

Specifically, decreases in the intake of high-fat meats were significantly associated with reductions in overall energy intake, fat intake percentage, and weight loss, suggesting that targeting these foods may enhance weight loss outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Decreases in High-Fat and/or High-Added-Sugar Food Group Intake Occur when a Hypocaloric, Low-Fat Diet Is Prescribed Within a Lifestyle Intervention: A Secondary Cohort Analysis. Sheikh, VK., Raynor, HA.[2021]

Diet plays a crucial role in cardiovascular disease risk, with high fat consumption linked to increased serum cholesterol levels; however, a study in Belgium found that dietary changes led to only a 3.5% reduction in cholesterol levels, highlighting the challenges in achieving significant dietary impact through physician guidance.

Current research suggests that a modified fat diet, which is rich in mono-unsaturated fatty acids, may be more effective than a low fat diet, especially for diabetic patients, as it offers practical benefits for reducing saturated fat intake.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Clinical approaches to healthier diet modifications. Muls, E., Vansant, G.[2017]

Diets high in fat are more likely to lead to body fat accumulation compared to diets high in carbohydrates, indicating that fat intake is a significant contributor to obesity.

Current evidence suggests that high sugar intake does not correlate with obesity, as it is negatively associated with obesity indexes, contrasting with the positive association found with high-fat diets.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Sugar and body weight regulation. Hill, JO., Prentice, AM.[2018]

In a study of 613 Canadian children aged 8-10, higher intake of added sugars, particularly from liquid sources, was linked to poorer diet quality, characterized by lower consumption of fruits, vegetables, and essential micronutrients.

Liquid added sugars were specifically associated with increased adiposity indicators, such as higher BMI and waist circumference, suggesting that reducing liquid sugar intake may be important for managing weight in children.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Associations between added sugar (solid vs. liquid) intakes, diet quality, and adiposity indicators in Canadian children. Wang, J., Shang, L., Light, K., et al.[2016]

Fructose consumption increases the enzyme ketohexokinase-C (KHK-C), which enhances lipogenesis and reduces fatty acid oxidation, contributing to metabolic dysfunction in mice fed a high-fat diet.

The study reveals that KHK-C modifies global protein acetylation, including the acetylation of CPT1α, leading to decreased levels of this protein and increased triglyceride accumulation, highlighting a novel mechanism by which dietary fructose exacerbates the effects of a high-fat diet.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Ketohexokinase-C regulates global protein acetylation to decrease carnitine palmitoyltransferase 1a-mediated fatty acid oxidation. Helsley, RN., Park, SH., Vekaria, HJ., et al.[2023]

Recent reviews of randomized controlled trials and cohort studies suggest that normal levels of added sugars in the human diet do not uniquely increase the risk of obesity, diabetes, or cardiovascular disease.

The findings indicate that common added sugars, like sucrose and high-fructose corn syrup, when consumed within typical dietary limits, do not pose additional health risks compared to other carbohydrates.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Added sugars and risk factors for obesity, diabetes and heart disease. Rippe, JM., Angelopoulos, TJ.[2022]

In a study involving 20 participants (10 normal weight and 10 obese), consuming HFCS-sweetened beverages for 2 weeks did not significantly affect body weight, insulin sensitivity, or other metabolic responses in either group.

Obese individuals exhibited lower physical activity levels and poorer metabolic profiles compared to normal weight individuals, but the short-term effects of HFCS consumption were similar regardless of weight classification.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Weight classification does not influence the short-term endocrine or metabolic effects of high-fructose corn syrup-sweetened beverages. Heden, TD., Liu, Y., Kearney, ML., et al.[2014]

In a study of 288 children, higher consumption of commercial complementary food (CF) in infancy was linked to increased added sugar intake both in infancy and later during pre-school and primary-school years.

The findings suggest that introducing home-made CF or selecting commercial CF without added sugar could help reduce overall sugar intake in young children, potentially preventing a preference for sweet tastes later in life.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Commercial complementary food consumption is prospectively associated with added sugar intake in childhood. Foterek, K., Buyken, AE., Bolzenius, K., et al.[2018]

A modified fat diet enriched with monounsaturated fats (MUFA) can effectively support weight loss through calorie counting or ad libitum intake, provided that high MUFA foods contribute no more than 20% of total energy.

This diet not only aids in weight loss but also offers health benefits such as improved metabolic control in Type 2 diabetes and reduced cardiovascular disease risk, thanks to its rich content of MUFA, antioxidants, and bio-active phytochemicals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Is a low fat diet the optimal way to cut energy intake over the long-term in overweight people? Walker, KZ., O'Dea, K.[2006]

In a study involving six healthy men, energy intake did not significantly increase with high-fat diets when compared to low-fat and medium-fat diets that had the same energy density, suggesting that fat does not inherently lead to higher energy consumption.

The findings indicate that neither carbohydrate nor fat intake is strictly regulated by the body's energy intake models, challenging the glucostatic and glycogenostatic theories of how we regulate food intake.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Covert manipulation of the dietary fat to carbohydrate ratio of isoenergetically dense diets: effect on food intake in feeding men ad libitum. Stubbs, RJ., Harbron, CG., Prentice, AM.[2014]

In a study of 2,197 adults, there was little evidence that consuming sugary fatty foods is linked to obesity, as the average intake of these foods was only about 12% to 15% of total energy intake.

Interestingly, the study found a weak negative correlation between sugar intake and BMI, suggesting that lower sugar consumption did not necessarily lead to lower body weight, especially in men.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Are high-fat, high-sugar foods and diets conducive to obesity? Gibson, SA.[2019]

In a study of 1719 French adults, those with excessive free sugar (FS) intake (41% of the population) had lower nutritional quality diets and higher overall energy consumption compared to those with acceptable FS levels.

To improve nutritional adequacy, both groups needed to increase their intake of fresh fruits, starchy foods, and plain yogurts, while those with excessive FS intake specifically benefited from reducing sugar-sweetened beverages and sweet products.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Individual Diet Modeling Shows How to Balance the Diet of French Adults with or without Excessive Free Sugar Intakes. Lluch, A., Maillot, M., Gazan, R., et al.[2023]

References

1. England pubmed.ncbi.nlm.nih.gov

How important is the relative balance of fat and carbohydrate as sources of energy in relation to health? [2022]

2. United States pubmed.ncbi.nlm.nih.gov

Decreases in High-Fat and/or High-Added-Sugar Food Group Intake Occur when a Hypocaloric, Low-Fat Diet Is Prescribed Within a Lifestyle Intervention: A Secondary Cohort Analysis. [2021]

3. England pubmed.ncbi.nlm.nih.gov

Clinical approaches to healthier diet modifications. [2017]

4. United States pubmed.ncbi.nlm.nih.gov

Sugar and body weight regulation. [2018]

5. Canada pubmed.ncbi.nlm.nih.gov

Associations between added sugar (solid vs. liquid) intakes, diet quality, and adiposity indicators in Canadian children. [2016]

6. Netherlands pubmed.ncbi.nlm.nih.gov

Ketohexokinase-C regulates global protein acetylation to decrease carnitine palmitoyltransferase 1a-mediated fatty acid oxidation. [2023]

7. England pubmed.ncbi.nlm.nih.gov

Added sugars and risk factors for obesity, diabetes and heart disease. [2022]

8. Canada pubmed.ncbi.nlm.nih.gov

Weight classification does not influence the short-term endocrine or metabolic effects of high-fructose corn syrup-sweetened beverages. [2014]

9. England pubmed.ncbi.nlm.nih.gov

Commercial complementary food consumption is prospectively associated with added sugar intake in childhood. [2018]

10. Netherlands pubmed.ncbi.nlm.nih.gov

Is a low fat diet the optimal way to cut energy intake over the long-term in overweight people? [2006]

11. England pubmed.ncbi.nlm.nih.gov

Covert manipulation of the dietary fat to carbohydrate ratio of isoenergetically dense diets: effect on food intake in feeding men ad libitum. [2014]

12. England pubmed.ncbi.nlm.nih.gov

Are high-fat, high-sugar foods and diets conducive to obesity? [2019]

13. Switzerland pubmed.ncbi.nlm.nih.gov

Individual Diet Modeling Shows How to Balance the Diet of French Adults with or without Excessive Free Sugar Intakes. [2023]