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Dietary Carbohydrate and Internal Body Fat (CARBFUNC)

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ClinicalTrials.gov Identifier: NCT03401970
Recruitment Status : Enrolling by invitation
First Posted : January 17, 2018
Last Update Posted : January 17, 2018
Sponsor:
Collaborator:
University of Bergen
Information provided by (Responsible Party):
Haukeland University Hospital

Brief Summary:
This is a 2-year randomized controlled trial to test the effect of dietary carbohydrates, both quality and quantity, on changes in internal body fat mass. Up to 250 women and men with obesity are recruited in Bergen, Norway, and randomized to one of the following normo- and isocaloric dietary patterns (same amount of protein, polyunsaturated fatty acids and moderate energy, 2,000 - 2,500 kcal per day): 1) a low-fat high-carbohydrate diet primarily with refined (e.g., flour-based) carbohydrate sources, 2) a low-fat high-carbohydrate diet based on minimally refined (e.g., cellular) carbohydrate sources, and 3) a very-high-fat low-carbohydrate diet.

Condition or disease Intervention/treatment Phase
Adiposity Behavioral: Acellular carbohydrate diet Behavioral: Cellular carbohydrate diet Behavioral: Low-carbohydrate high-fat diet Not Applicable

Detailed Description:

Obesity, and high internal fat storage in particular, represents a tremendous and increasing health challenge across the world, and is linked to the recent introduction and globalization of an ultra-processed food supply largely based on refined carbohydrates. However, more high-quality studies are needed to directly assess the role of carbohydrate quality in abdominal adiposity. We also need studies with greater long-term adherence to prescribed food profiles, which may be achievied with the help of new electronic tools such as meal planning applications.

The participants select and plan all meals among a list of carefully designed options, using an application/recipe booklet developed for the study. Each recipe/meal/snack is designed to fully comply with the overall macronutrient- and dietary profile for the respective groups. We will further instruct the participants to record their meal choices during three days every 14 days, and to record all deviations throughout the intervention.

Enrolled participants are invited to study visits at baseline and after 3, 6, 9, 12 and 24 months. At all or some of these time points, the participants provide biological samples (blood, urine and feces, and for some, adipose and/or muscle tissue) and undergo phenotyping, e.g., measurement of body weight and fat mass by bioelectrical impedance analysis and low-radiation CT imaging, and a standardized meal test with blood sample collection up to 4 hours postprandially. In addition, participants will be asked to fill out a collection of questionnaires that assess quality of life, motivation, fatigue, gastrointestinal health, appetite and physical activity. We ask the participants to maintain the same level of physical activity throughout the study.

The primary outcome measure is change in internal body fat mass (visceral adipose tissue) measured by CT imaging. Secondary outcome measures include change in 2-hour postprandial serum concentrations of insulin, change in 4-hour postprandial serum concentrations of triacylglycerols, and change in fecal microbiota composition measured by 16S sequencing.


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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 150 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Dietary Carbohydrate and Internal Body Fat Mass in Women and Men With Obesity
Actual Study Start Date : January 3, 2018
Estimated Primary Completion Date : April 2020
Estimated Study Completion Date : December 2020

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Carbohydrates

Arm Intervention/treatment
Active Comparator: Acellular carbohydrate diet
Prescribed dietary pattern. Carbohydrates from acellular sources, e.g., refined flour/bakery products, at least 500 grams of fruits/vegetables per day, and a macronutrient composition within typical nutritional recommendations for the general population.
Behavioral: Acellular carbohydrate diet
Participants will be asked to consume 2,000 - 2,500 kcals, thereof 45 energy percent (E%) carbohydrate (up to 5 E% added sugar), 30 E% fat (10-12 E% saturated fatty acids and 7-10 E% polyunsaturated fatty acids) and 17 E% protein. They will use an original online/smartphone application that provides choices of meals/food combinations/recipes corresponding to their prescribed macronutrient profile and dietary pattern. Participants are asked to complete 3-day dietary records every 14 days throughout the study, and to report any deviations from the planned interventions.

Experimental: Cellular carbohydrate diet
Prescribed dietary pattern. Carbohydrates from cellular sources, e.g., root vegetables, fruits, whole-grain rice, non-flour grain products, at least 500 grams of fruits/vegetables per day, and a macronutrient composition within typical nutritional recommendations for the general population similar to the acellular carbohydrate diet.
Behavioral: Cellular carbohydrate diet
Participants will be asked to consume 2,000 - 2,500 kcals, thereof 45 energy percent (E%) carbohydrate (up to 1 E% added sugar), 38 E% fat (10-12 E% saturated fatty acids and 7-10 E% polyunsaturated fatty acids) and 17 E% protein. They will use an original online/smartphone application that provides choices of meals/food combinations/recipes corresponding to their prescribed macronutrient profile and dietary pattern. Participants are asked to complete 3-day dietary records every 14 days throughout the study, and to report any deviations from the planned interventions.

Experimental: Low-carbohydrate high-fat diet
Prescribed dietary pattern. Energy largely from fat, cellular carbohydrate sources, and otherwise similar food types as in the acellular/cellular carbohydrate diets including at least 500 grams of fruits/vegetables per day.
Behavioral: Low-carbohydrate high-fat diet
Participants will be asked to consume 2,000 - 2,500 kcals, thereof 10 energy percent (E%) carbohydrate (up to 1 E% added sugar), 73 E% fat (30 E% saturated fatty acids and 7-10 E% polyunsaturated fatty acids) and 17 E% protein. They will use an original online/smartphone application that provides choices of meals/food combinations/recipes corresponding to their prescribed macronutrient profile and dietary pattern. Participants are asked to complete 3-day dietary records every 14 days throughout the study, and to report any deviations from the planned interventions.




Primary Outcome Measures :
  1. Change in internal body fat [ Time Frame: Baseline and 6, 12 and 24 months ]
    Visceral fat mass (cm3) measured by computed tomography (CT) imaging


Secondary Outcome Measures :
  1. Change in postprandial insulin [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating insulin concentrations measured before and 2 hours after intake of a standardized mixed meal

  2. Change in postprandial C-peptide [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating C-peptide concentrations measured before and 2 hours after intake of a standardized mixed meal

  3. Change in postprandial triacylglycerol [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Triacylglycerol concentrations measured before and 4 hours after intake of a mixed meal

  4. Change in postprandial area under the curve (AUC) glucose [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating glucose measured before and after 30, 60, 90, 120 and 240 minutes after intake of a standardized mixed meal

  5. Change in postprandial non-esterified fatty acids [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating non-esterified fatty acid concentrations before and after 60, 120 and 240 minutes after intake of a standardized mixed meal

  6. Change in fecal microbiome composition [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Microbiome composition measured by 16S sequencing

  7. Change in liver density [ Time Frame: Baseline and 6, 12 and 24 months ]
    Calculated as liver/spleen attenuation index (Hounsfield units) based on quantification by computed tomography (CT) imaging

  8. Change in pericardial fat mass [ Time Frame: Baseline and 6, 12 and 24 months ]
    Pericardial fat mass (cm3) measured by computed tomography (CT) imaging

  9. Change in abdominal subcutaneous fat mass [ Time Frame: Baseline and 6, 12 and 24 months ]
    Abdominal subcutaneous fat mass (cm3) measured by computed tomography (CT) imaging

  10. Change in coronary artery calcification (CAC) [ Time Frame: Baseline and 6, 12 and 24 months ]
    CAC score calculated based on computed tomography (CT) imaging

  11. Change in waist circumference [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Waist circumference (cm) measured by a measuring tape

  12. Change in body-mass index [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Body-mass index measured as body weight (kg) divided by height (m) squared

  13. Change in fasting insulin [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating fasting insulin concentrations

  14. Change in fasting C-peptide [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating fasting C-peptide concentrations

  15. Change in fasting TAG [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating fasting triacylglycerol concentrations

  16. Change in fasting HDL cholesterol [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating fasting high-density lipoprotein cholesterol (HDL-C)

  17. Change in TAG/HDL-C ratio [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    The ratio of circulating fasting triacylglycerol (TAG) and high-density lipoprotein cholesterol (HDL-C)

  18. Change in fasting LDL cholesterol [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating fasting low-density lipoprotein cholesterol (LDL-C)

  19. Change in apolipoprotein profile [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating fasting apolipoprotein profile measured by multiplex ELISA

  20. Change in circulating and urine metabolites associated with one-carbon metabolism [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Circulating metabolites in the serine, glycine and histidine pathways measured in the fasted state by GC-MS/MS

  21. Change in total fat mass [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Total fat mass measured by bioimpedance analysis (BIA)

  22. Change in lean mass [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Lean mass will be measured by bioimpedance analysis (BIA)

  23. Change in appetite/fullness [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Subjective appetite and fullness assessed and quantified by the VAS questionnaire

  24. Change in gastrointestinal symptoms by the Roma III questionnaire [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Gastrointestinal health will be surveyed and quantified by a questionnaire for diagnosis of irritable bowel syndrome (Roma III)

  25. Change in gastrointestinal symptoms by the IBS-SSS questionnaire [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    Gastrointestinal health will be surveyed by the (IBS-SSS) questionnaire

  26. Change in fatigue [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    The Fatigue Impact Scale will be used to compute a total score for fatigue by summing up the scores for subclasses as follows: cognitive functioning (10 items, subscale range: 0-40), physical functioning (10 items, subscale range: 0-40), and psychosocial functioning (20 items, subscale range: 0-80). The statements are ranged on a five-level scale (0 = no problem to 4 = extreme problems), giving a maximum total FIS score of 160 (total scale range: 0-160) where low scores indicate less fatigue-related issues

  27. Change in perception of health [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    The RAND-36 questionnaire will be used to assess perceived health / wellbeing

  28. Change in quality of life [ Time Frame: Baseline and 3, 6, 9, 12 and 24 months ]
    The SF-NDI questionnaire will be used to assess quality of life / psychological wellbeing



Information from the National Library of Medicine

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Ages Eligible for Study:   20 Years to 55 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Body-mass index (BMI) equal to or above 30 kg/m2 and/or waist circumference equal to or above 102 cm for men and 88 cm for women
  • Weight stable during the last 2 months before start of the study (less than 5 % change in body weight up or down)
  • No known diabetes or consumption of diabetes medication
  • Desire to follow a specified dietary pattern using specific recipes throughout the time of the study period
  • Ability to periodically record food intake using a specially designed app for the study

Exclusion Criteria:

  • Use of statins and/or diabetes medication
  • Recent surgical or antibiotics treatment during the last 2 months before start of the study
  • Chronic inflammatory bowel disease
  • Serious disease
  • Smoking
  • Pregnancy or breast feeding
  • Alcohol consumption during the study of more than 2 alcohol units per day (1 unit = 15 ml (12.8 g) pure alcohol)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03401970


Locations
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Norway
Forskningsenhet for helseundersøkelser (research unit for clinical trials), Department of Clinical Science, University of Bergen
Bergen, Norway, 5021
Sponsors and Collaborators
Haukeland University Hospital
University of Bergen
Investigators
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Principal Investigator: Simon N Dankel, PhD University of Bergen
Study Director: Gunnar Mellgren, MD PhD Haukeland University Hospital

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Responsible Party: Haukeland University Hospital
ClinicalTrials.gov Identifier: NCT03401970     History of Changes
Other Study ID Numbers: 2017/621
First Posted: January 17, 2018    Key Record Dates
Last Update Posted: January 17, 2018
Last Verified: January 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Keywords provided by Haukeland University Hospital:
Body composition
Internal body fat
Dietary pattern
Dietary carbohydrate

Additional relevant MeSH terms:
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Nutrients
Growth Substances
Physiological Effects of Drugs