AdiposityCARBFUNCNCT03401970
Dietary Carbohydrate and Internal Body Fat
A study testing Acellular carbohydrate diet, Cellular carbohydrate diet and Low-carbohydrate high-fat diet in people with Adiposity, run by Haukeland University Hospital at 1 site in Norway.
Trial 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… Read more about this study
- Who is it for?
- Ages 20 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Adiposity
- What is being tested?
- Acellular carbohydrate diet, Cellular carbohydrate diet and Low-carbohydrate high-fat diet
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 193 participants
- Where
- 1 siteNorway
- Study dates
- 3 Jan 2018to 24 Mar 2021
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
Who cannot join
- 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)
Trial locations and contacts
1 site in 1 country.
Norway1 site
Forskningsenhet for helseundersøkelser (research unit for clinical trials), Department of Clinical Science, University of Bergen
Bergen, 5021
About this study
Official title: Dietary Carbohydrate and Internal Body Fat Mass in Women and Men With Obesity
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.
Read the 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.
- Conditions
- Adiposity
- Being tested
- Acellular carbohydrate diet, Cellular carbohydrate diet, Low-carbohydrate high-fat diet
- Keywords
- Body composition, Internal body fat, Dietary pattern, Dietary carbohydrate
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Acellular carbohydrate dietBehavioural
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.
Cellular carbohydrate dietBehavioural
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.
Low-carbohydrate high-fat dietBehavioural
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.
| Study group | Role | What they receive |
|---|---|---|
| Acellular carbohydrate diet | Active comparator | 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. Receives: Behavioral: Acellular carbohydrate diet |
| Cellular carbohydrate diet | Experimental | 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. Receives: Behavioral: Cellular carbohydrate diet |
| Low-carbohydrate high-fat diet | Experimental | 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. Receives: Behavioral: Low-carbohydrate high-fat diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in internal body fat
Visceral fat mass (cm3) measured by computed tomography (CT) imaging
Measured: Baseline and 6, 12 and 24 months
Secondary outcomes (28)
Change in postprandial insulin
Circulating insulin concentrations measured before and 2 hours after intake of a standardized mixed meal
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in postprandial C-peptide
Circulating C-peptide concentrations measured before and 2 hours after intake of a standardized mixed meal
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in postprandial triacylglycerol
Triacylglycerol concentrations measured before and 4 hours after intake of a mixed meal
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in postprandial area under the curve (AUC) glucose
Circulating glucose measured before and after 30, 60, 90, 120 and 240 minutes after intake of a standardized mixed meal
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in postprandial non-esterified fatty acids
Circulating non-esterified fatty acid concentrations before and after 60, 120 and 240 minutes after intake of a standardized mixed meal
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in fecal microbiome composition
Microbiome composition measured by 16S sequencing
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in liver density
Calculated as liver/spleen attenuation index (Hounsfield units) based on quantification by computed tomography (CT) imaging
Measured: Baseline and 6, 12 and 24 months
Change in pericardial fat mass
Pericardial fat mass (cm3) measured by computed tomography (CT) imaging
Measured: Baseline and 6, 12 and 24 months
Change in abdominal subcutaneous fat mass
Abdominal subcutaneous fat mass (cm3) measured by computed tomography (CT) imaging
Measured: Baseline and 6, 12 and 24 months
Change in coronary artery calcification (CAC)
CAC score calculated based on computed tomography (CT) imaging
Measured: Baseline and 6, 12 and 24 months
Change in waist circumference
Waist circumference (cm) measured by a measuring tape
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in body-mass index
Body-mass index measured as body weight (kg) divided by height (m) squared
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting insulin
Circulating fasting insulin concentrations
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting C-peptide
Circulating fasting C-peptide concentrations
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting TAG
Circulating fasting triacylglycerol concentrations
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting HDL cholesterol
Circulating fasting high-density lipoprotein cholesterol (HDL-C)
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in TAG/HDL-C ratio
The ratio of circulating fasting triacylglycerol (TAG) and high-density lipoprotein cholesterol (HDL-C)
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting LDL cholesterol
Circulating fasting low-density lipoprotein cholesterol (LDL-C)
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in apolipoprotein profile
Circulating fasting apolipoprotein profile measured by multiplex ELISA
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in circulating and urine metabolites associated with one-carbon metabolism
Circulating metabolites in the serine, glycine and histidine pathways measured in the fasted state by GC-MS/MS
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in total fat mass
Total fat mass measured by bioimpedance analysis (BIA)
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in lean mass
Lean mass will be measured by bioimpedance analysis (BIA)
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in appetite/fullness
Subjective appetite and fullness assessed and quantified by the VAS questionnaire
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in gastrointestinal symptoms by the Roma III questionnaire
Gastrointestinal health will be surveyed and quantified by a questionnaire (Rome III Diagnostic Criteria for Irritable Bowel Syndrome (IBS)). The questionnaire surveys criteria for diagnosis of IBS within a 12-week period. The criteria for IBS are based on recurrent abdominal pain or discomfort, 3 days per month in the last 3 months (12 weeks), associated with ≥2 of the following criteria: 1.Improvement with defecation; 2. Onset associated with a change in stool frequency; 3. Onset associated with a change in stool form (appearance). The criteria are fulfilled with symptoms onset 6 months prior to diagnosis.
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in gastrointestinal symptoms by the IBS-SSS questionnaire
Gastrointestinal health will be surveyed by the IBS-SSS questionnaire. Scores on the IBS-SSS range from 0 to 500 with higher scores indicating more severe symptoms. Subjects can be categorized as having mild (75-175), moderate (175-300), or severe (>300) IBS. A decrease of 50 points is associated with a clinically meaningful improvement. Each question on the VAS ranges from 0-100mm, where higher score indicates more severe symptoms.
The categorization based on scores (total possible score = 500) are as follows:
0-75 = not IBS 75-175= mild IBS 175-300 = moderate IBS 300-500 = severe IBS
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in fatigue
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.
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in perception of health / quality of life
Obesity-specific quality of life is measured with "Patient-Reported Outcomes in Obesity" (PROS), which consists of 8 items tapping how different life domains are affected by obesity. PROS have one overall score, ranging from 0 (optimal) to 3 (poorest).
Generic health-related quality of life is measured with RAND-36, which consists of dimensions ranging from 0 (poorest) to 100 (optimal). There are 8 subscales; physical functioning, physical role functioning, bodily pain, general health, vitality, social functioning, emotional role functioning and mental health. In addition, RAND-36 also have 2 summary scores: the physical component summary (PCS) (tapping from physical functioning, physical role functioning, bodily pain and general health) and mental component summary (MCS) (tapping from vitality, social functioning, emotional role functioning and mental health).
Measured: Baseline and 3, 6, 9, 12 and 24 months
Change in quality of life related to gastrointestinal symptoms
The SF-NDI (Short-Form Nepean Dyspepsia Index (SF-NDI)) questionnaire will be used to assess quality of life / psychological wellbeing related to gastrointestinal symptoms. The 10-item SF-NDI was constructed and validated in patients with functional gastrointestinal disorders for measuring health-related quality of life. The 10-item short form includes five subscales: tension, interference with daily activities, eating/drinking, knowledge/control, and work/study, and each subscale contains two items. The items were measured by a 5-point graded Likert scale from 1 to 5. A total sum score for quality of life and a sum score for each of the five subscales were calculated by adding up scores for each item (range of total quality of life, 10-50; range of each subscale, 2-10). Higher scores indicate worse functioning or symptoms.
Measured: Baseline and 3, 6, 9, 12 and 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Jan 2018
- Study start3 Jan 2018
- Primary completion20 May 2020
- Study completion24 Mar 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for AdiposityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 193 participants (actual)
Sponsor and investigators
- Lead sponsor
- Haukeland University Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- University of Bergen
- Responsible party
- Sponsor
- Investigators
- Simon N Dankel, PhD, Principal investigator, University of BergenGunnar Mellgren, MD PhD, Study director, Haukeland University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03401970
- Sponsor's protocol ID
- 2017/621
- Acronym
- CARBFUNC
- Status last verified
- Apr 2021
- First submitted
- 23 Aug 2017
- Last updated
- 2 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Bratveit M, Laupsa Borge J, Bjornstad T, Sommersten C, McCann A, Arslan Lied G, Nygard O, Mellgren G, Dierkes J, Nitter Dankel S. Marked Changes in One-Carbon Metabolism on a Low-Carbohydrate High-Fat Diet: A Randomized Controlled Trial (CARBFUNC). J Nutr. 2026 Jul;156(7):101625. doi: 10.1016/j.tjnut.2026.101625. Epub 2026 Jun 2.
PubMed 42235826Jensen C, Sommersten CH, Laupsa-Borge J, Storas I, Valeur J, Mellgren G, Dierkes J, Dankel SN, Lied GA. Quality and quantity of carbohydrates, faecal short-chain fatty acids and gastrointestinal symptoms - results from a randomised, controlled trial (CARBFUNC). Clin Nutr. 2025 Jan;44:54-64. doi: 10.1016/j.clnu.2024.11.041. Epub 2024 Nov 26.
PubMed 39631208Sommersten CH, Gjerde ES, Laupsa-Borge J, Andersen AI, Lawrence-Archer L, McCann A, Hansson P, Raza GS, Herzig KH, Lied GA, Martins C, Mellgren G, Dierkes J, Dankel SN. Relationship between Ketones, Ghrelin, and, Appetite on Isocaloric Diets with Varying Carbohydrate Quality and Amount: Results from a Randomized Controlled Trial in People with Obesity (CARBFUNC). J Nutr. 2023 Feb;153(2):459-469. doi: 10.1016/j.tjnut.2022.12.030. Epub 2022 Dec 29.
PubMed 36894239Sommersten CH, Laupsa-Borge J, Andersen AIO, Fasmer KE, Holmefjord MA, Revheim I, Johannessen KK, Naesheim NT, Storas I, Leikanger T, Amundsen K, Skjerve KL, Lawrence-Archer L, Spjelkavik C, Haldorsen I, Lindseth I, Dierkes J, Mellgren G, Dankel SN. Diets differing in carbohydrate cellularity and amount similarly reduced visceral fat in people with obesity - a randomized controlled trial (CARBFUNC). Clin Nutr. 2022 Oct;41(10):2345-2355. doi: 10.1016/j.clnu.2022.08.028. Epub 2022 Sep 5.
PubMed 36116147
Study at a glance
From the registry record, last updated by the sponsor on 2 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dietary Carbohydrate and Internal Body Fat Mass in Women and Men With Obesity
- ClinicalTrials.gov ID
- NCT03401970
- Acronym / sponsor ID
- CARBFUNC / 2017/621
- Conditions
- Adiposity
- Keywords
- Body composition, Internal body fat, Dietary pattern, Dietary carbohydrate
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 193 participants (actual)
- Lead sponsor
- Haukeland University HospitalUniversity, hospital or other
- Collaborators
- University of Bergen
- Study start
- 3 Jan 2018 (actual)
- Primary completion
- 20 May 2020 (actual)
- Study completion
- 24 Mar 2021 (actual)
- First posted
- 17 Jan 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Acellular carbohydrate diet | Active comparator | Behavioral: Acellular carbohydrate dietPrescribed 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. |
| Cellular carbohydrate diet | Experimental | Behavioral: Cellular carbohydrate dietPrescribed 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. |
| Low-carbohydrate high-fat diet | Experimental | Behavioral: Low-carbohydrate high-fat dietPrescribed 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. |
Who may qualify
- Ages
- 20 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (7 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Acellular carbohydrate dietParticipants 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. | Behavioural | Acellular carbohydrate diet |
| Cellular carbohydrate dietParticipants 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. | Behavioural | Cellular carbohydrate diet |
| Low-carbohydrate high-fat dietParticipants 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. | Behavioural | Low-carbohydrate high-fat diet |
Primary outcome
Change in internal body fat
Time frame: Baseline and 6, 12 and 24 months
Visceral fat mass (cm3) measured by computed tomography (CT) imaging
28 secondary outcomes
Change in postprandial insulin
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in postprandial C-peptide
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in postprandial triacylglycerol
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in postprandial area under the curve (AUC) glucose
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in postprandial non-esterified fatty acids
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in fecal microbiome composition
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in liver density
Time frame: Baseline and 6, 12 and 24 months
Change in pericardial fat mass
Time frame: Baseline and 6, 12 and 24 months
Change in abdominal subcutaneous fat mass
Time frame: Baseline and 6, 12 and 24 months
Change in coronary artery calcification (CAC)
Time frame: Baseline and 6, 12 and 24 months
Change in waist circumference
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in body-mass index
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting insulin
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting C-peptide
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting TAG
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting HDL cholesterol
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in TAG/HDL-C ratio
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in fasting LDL cholesterol
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in apolipoprotein profile
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in circulating and urine metabolites associated with one-carbon metabolism
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in total fat mass
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in lean mass
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in appetite/fullness
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in gastrointestinal symptoms by the Roma III questionnaire
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in gastrointestinal symptoms by the IBS-SSS questionnaire
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in fatigue
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in perception of health / quality of life
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Change in quality of life related to gastrointestinal symptoms
Time frame: Baseline and 3, 6, 9, 12 and 24 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Oct 2026.
- Derived from this study: PubMed 42235826Bratveit M, Laupsa Borge J, Bjornstad T, Sommersten C, McCann A, Arslan Lied G, Nygard O, Mellgren G, Dierkes J, Nitter Dankel S. Marked Changes in One-Carbon Metabolism on a Low-Carbohydrate High-Fat Diet: A Randomized Controlled Trial (CARBFUNC). J Nutr. 2026 Jul;156(7):101625. doi: 10.1016/j.tjnut.2026.101625. Epub 2026 Jun 2.
- Derived from this study: PubMed 39631208Jensen C, Sommersten CH, Laupsa-Borge J, Storas I, Valeur J, Mellgren G, Dierkes J, Dankel SN, Lied GA. Quality and quantity of carbohydrates, faecal short-chain fatty acids and gastrointestinal symptoms - results from a randomised, controlled trial (CARBFUNC). Clin Nutr. 2025 Jan;44:54-64. doi: 10.1016/j.clnu.2024.11.041. Epub 2024 Nov 26.
- Derived from this study: PubMed 36894239Sommersten CH, Gjerde ES, Laupsa-Borge J, Andersen AI, Lawrence-Archer L, McCann A, Hansson P, Raza GS, Herzig KH, Lied GA, Martins C, Mellgren G, Dierkes J, Dankel SN. Relationship between Ketones, Ghrelin, and, Appetite on Isocaloric Diets with Varying Carbohydrate Quality and Amount: Results from a Randomized Controlled Trial in People with Obesity (CARBFUNC). J Nutr. 2023 Feb;153(2):459-469. doi: 10.1016/j.tjnut.2022.12.030. Epub 2022 Dec 29.
- Derived from this study: PubMed 36116147Sommersten CH, Laupsa-Borge J, Andersen AIO, Fasmer KE, Holmefjord MA, Revheim I, Johannessen KK, Naesheim NT, Storas I, Leikanger T, Amundsen K, Skjerve KL, Lawrence-Archer L, Spjelkavik C, Haldorsen I, Lindseth I, Dierkes J, Mellgren G, Dankel SN. Diets differing in carbohydrate cellularity and amount similarly reduced visceral fat in people with obesity - a randomized controlled trial (CARBFUNC). Clin Nutr. 2022 Oct;41(10):2345-2355. doi: 10.1016/j.clnu.2022.08.028. Epub 2022 Sep 5.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Simon N Dankel, PhD principal investigator
University of Bergen
Gunnar Mellgren, MD PhD study director
Haukeland University Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Acellular carbohydrate diet, Cellular carbohydrate diet and Low-carbohydrate high-fat diet in people with Adiposity, run by Haukeland University Hospital at 1 site in Norway.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 2 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Norway. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in internal body fat (time frame: Baseline and 6, 12 and 24 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03401970, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Oct 2026.