Ketogenic and Carnivore (Lion) Diets for Inflammatory Bowel Disease and Rheumatoid Arthritis

April 13, 2026 updated by: Fuller Research Foundation

Effectiveness and Efficacy of a Ketogenic or Carnivore (Lion) Diet for Quality Life and Symptom Burden in Individuals With Symptomatic Inflammatory Bowel Disease or Rheumatoid Arthritis: A Randomized Controlled Clinical Trial

This study is a randomized controlled clinical trial evaluating whether two therapeutic dietary approaches - a ketogenic diet and a carnivore (lion) diet - can improve quality of life, reduce symptoms, and influence measures of disease activity in adults with inflammatory bowel disease [ulcerative colitis and Crohn's disease] (IBD) or rheumatoid arthritis (RA).

Participants will be randomized into one of three groups: 1) Ketogenic Diet, 2) Carnivore (Lion) Diet or 3) Wait-List Control.

Participants randomized to a dietary group (ketogenic diet or carnivore diet) will be provided guidance on their specific dietary therapy and answer questions about their symptoms and quality of life at different intervals over a 24 week period. Participants will also complete laboratory testing at different intervals to assess for changes in nutritional status, cardiometabolic health and markers of immune activation and inflammation.

Participants initially placed on the wait-list group will be asked similar questions about their symptoms and quality of life and complete the same laboratory testing as participants in a dietary group. Participants on the wait list will then be compared to participants following a specific dietary pattern to assess for any differences between the 2 groups. After 12 weeks, participants on the wait list will be randomized to a dietary group (ketogenic diet or carnivore diet) and followed in a similar fashion for an additional 12 week period.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The primary goal of this study is to determine whether ketogenic or carnivore dietary therapy improves, health-related quality of life, disease specific symptom burden or objective inflammatory markers in patients with a history of IBD or RA.

Given the limited prospective data on carnivore (lion) diet approaches for addressing autoimmune conditions, the study aims to assess feasibility of implementation as well as overall safety including the documentation of common adverse events, changes to nutritional status or changes to cardiometabolic status including blood lipids.

Total participation time is approximately 27 weeks including a 3-week baseline run-in and a 24-week dietary intervention period divided into 2, 12-week phases.

Randomization and 3 week run-in period

Participants will be randomized in a 2-2-2 schema, stratified by disease state (IBD or RA), to the carnivore (lion) diet, ketogenic diet, or placed on a wait-list. Participants will receive an at-home blood ketone and blood glucose monitoring device and a digital body composition scale. Participants will discontinue any supplements started within one month of study enrollment.

Participants will then complete questionnaires and laboratory testing across several areas to include:

Baseline quality-of-life, psychometric, and disease-specific symptom questionnaires Baseline body composition assessment and a historical food frequency questionnaire Baseline qualitative and quantitative analysis of self reported dietary intake Baseline at-home finger-stick blood ketone and blood glucose monitoring Baseline fasted blood collection and at-home stool collection

Initial dietary intervention and support

Participants randomized into a dietary intervention group will receive educational materials, including recommended foods and structured meal plans, with ongoing virtual access to medical and nutrition providers. Participants will join scheduled group telehealth sessions tailored to their dietary intervention to review study procedures, ask questions, and receive support within a community of fellow participants. Participants will receive ongoing telehealth monitoring from the medical and nutritional staff.

Participants will complete certain study questionnaires around dietary adherence, progress and satisfaction at different intervals throughout the study. Participants will also also complete qualitative and quantitative dietary journals alongside at home blood ketone and blood glucose at various intervals throughout the study.

Midpoint questionnaires and testing

After the first 12 weeks of their specified dietary intervention, participants will complete questionnaires and testing similar to their baseline to assess for any initial changes. Participants initially placed on the wait-list will be asked similar questions about their symptoms and quality of life and complete the same laboratory testing as participants in a dietary group for the purposes of comparison at 12 weeks.

Following the completion of their midpoint testing, participants on the wait list will be randomized to a dietary group (ketogenic diet or carnivore diet) and complete the same initial 12 week dietary program as those originally randomized to a dietary group. Individuals in the original dietary groups will continue for an additional 12 weeks in their specified dietary interventions OR voluntarily elect to "cross-over" into the other dietary intervention arm with the approval of the clinical team. Participants in either dietary intervention group will continue to receive ongoing support, education and virtual access to the medical and nutritional team.

Final Questionnaires and Testing

After 24 weeks (2, 12 week dietary phases), all study participants will repeat baseline study questionnaires and laboratory testing for the sake of comparison of key outcome measures at 24 weeks.

Study Type

Interventional

Enrollment (Estimated)

160

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosed with medically verifiable IBD or medically verifiable RA
  • Current personal residence in the continental U.S.
  • Willingness and ability to follow dietary protocols

Exclusion Criteria:

  • Inability to provide consent
  • Individuals with Type 1 or Type II Diabetes on prescription medications including insulin
  • Outside of the age or BMI criteria
  • No medically definitive or verifiable diagnosis of IBD or RA
  • History of strictures or fistula (IBD)
  • History of blood transfusion in the previous 6 months
  • Pregnancy
  • 6 months Postpartum
  • Breastfeeding
  • On other medications outside of FDA approved medications
  • Current initiation of disease modifying or biologic medication within the past 2 months
  • Unable to complete, for any reason, the initial 3-week run-in period prior to the beginning of the formal study intervention
  • Non-English Speaking
  • Organ failure of any kind including heart, liver and kidney failure or disease
  • History of malignancy within the last year prior to enrollment
  • Red meat allergy, alpha-gal allergy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Ketogenic Diet 24 Weeks
Participants with IBD or RA randomized initially to receive dietary counseling regarding the ketogenic diet for up to 24 weeks
Behavioral: Ketogenic diet

The ketogenic diet is a high fat, moderate protein, and very low carbohydrate nutritional approach designed to shift the body's primary energy source from glucose to ketones, compounds produced in the liver from fat metabolism. This state of nutritional ketosis typically occurs when carbohydrate intake is restricted to 20-50 grams per day, though the exact threshold varies based on individual factors such as muscle mass, insulin sensitivity, and physical activity.

Participants will receive nutritional guidance for the ketogenic diet in a virtual setting via both synchronous and asynchronous engagement including group telehealth sessions, dietary education guides/food lists, quantitative sample meals plans and ongoing messaging capacity with the clinical team for the duration of the dietary intervention.
Experimental: Carnivore (Lion) Diet 24 Weeks
Participants with IBD or RA randomized initially to receive dietary counseling regarding the carnivore (lion) diet for up to 24 weeks
Behavioral: Carnivore (Lion) Diet

The carnivore (lion) diet is a more restrictive form of a ketogenic diet that is intended as an elimination dietary protocol composed exclusively of ruminant meats (beef, lamb, bison, venison, goat, moose, elk), salt, and water. A broader carnivore diet includes more animal foods such as additional meats, fish, eggs, and some dairy. It excludes, however, all plant foods including vegetables, fruits, grains, legumes, nuts, seeds, or plant-derived oils.

Participants will receive nutritional guidance for the carnivore (lion) and the broader carnivore diet in a virtual setting via both synchronous and asynchronous engagement including group telehealth sessions, dietary education guides/food lists, quantitative sample meals plans and ongoing messaging capacity with the clinical team for the duration of the dietary intervention.
No Intervention: Wait List 12 Weeks
Participants with IBD or RA randomized initially to a 12 week waitlist who will continue their baseline dietary pattern WITHOUT specific dietary guidance/intervention
Experimental: Carnivore (Lion) Diet for 12 weeks AFTER Wait-List
Participants with IBD or RA randomized initially to the wait-list for 12 weeks who are then randomized to receive dietary counseling regarding the carnivore (lion) diet for a subsequent 12 weeks
Behavioral: Carnivore (Lion) Diet

The carnivore (lion) diet is a more restrictive form of a ketogenic diet that is intended as an elimination dietary protocol composed exclusively of ruminant meats (beef, lamb, bison, venison, goat, moose, elk), salt, and water. A broader carnivore diet includes more animal foods such as additional meats, fish, eggs, and some dairy. It excludes, however, all plant foods including vegetables, fruits, grains, legumes, nuts, seeds, or plant-derived oils.

Participants will receive nutritional guidance for the carnivore (lion) and the broader carnivore diet in a virtual setting via both synchronous and asynchronous engagement including group telehealth sessions, dietary education guides/food lists, quantitative sample meals plans and ongoing messaging capacity with the clinical team for the duration of the dietary intervention.
Experimental: Ketogenic Diet for 12 Weeks AFTER Wait-List
Participants with IBD or RA randomized initially to the wait-list for 12 weeks who are then randomized to receive dietary counseling regarding the carnivore (lion) diet for a subsequent 12 weeks
Behavioral: Ketogenic diet

The ketogenic diet is a high fat, moderate protein, and very low carbohydrate nutritional approach designed to shift the body's primary energy source from glucose to ketones, compounds produced in the liver from fat metabolism. This state of nutritional ketosis typically occurs when carbohydrate intake is restricted to 20-50 grams per day, though the exact threshold varies based on individual factors such as muscle mass, insulin sensitivity, and physical activity.

Participants will receive nutritional guidance for the ketogenic diet in a virtual setting via both synchronous and asynchronous engagement including group telehealth sessions, dietary education guides/food lists, quantitative sample meals plans and ongoing messaging capacity with the clinical team for the duration of the dietary intervention.
Experimental: Voluntary Crossover - Ketogenic Diet to Carnivore (Lion) Diet AFTER 12 weeks
Participants with IBD or RA randomized initially to the ketogenic diet for 12 weeks who voluntarily choose to crossover to the carnivore (lion) diet intervention for the final 12 weeks
Behavioral: Ketogenic diet

The ketogenic diet is a high fat, moderate protein, and very low carbohydrate nutritional approach designed to shift the body's primary energy source from glucose to ketones, compounds produced in the liver from fat metabolism. This state of nutritional ketosis typically occurs when carbohydrate intake is restricted to 20-50 grams per day, though the exact threshold varies based on individual factors such as muscle mass, insulin sensitivity, and physical activity.

Participants will receive nutritional guidance for the ketogenic diet in a virtual setting via both synchronous and asynchronous engagement including group telehealth sessions, dietary education guides/food lists, quantitative sample meals plans and ongoing messaging capacity with the clinical team for the duration of the dietary intervention.

Behavioral: Carnivore (Lion) Diet

The carnivore (lion) diet is a more restrictive form of a ketogenic diet that is intended as an elimination dietary protocol composed exclusively of ruminant meats (beef, lamb, bison, venison, goat, moose, elk), salt, and water. A broader carnivore diet includes more animal foods such as additional meats, fish, eggs, and some dairy. It excludes, however, all plant foods including vegetables, fruits, grains, legumes, nuts, seeds, or plant-derived oils.

Participants will receive nutritional guidance for the carnivore (lion) and the broader carnivore diet in a virtual setting via both synchronous and asynchronous engagement including group telehealth sessions, dietary education guides/food lists, quantitative sample meals plans and ongoing messaging capacity with the clinical team for the duration of the dietary intervention.
Experimental: Voluntary Crossover - Carnivore (Lion) Diet to Ketogenic Diet AFTER 12 weeks
Participants with IBD or RA randomized initially to the carnivore (lion) diet for 12 weeks who voluntarily choose to crossover to the ketogenic diet intervention for the final 12 weeks
Behavioral: Ketogenic diet

The ketogenic diet is a high fat, moderate protein, and very low carbohydrate nutritional approach designed to shift the body's primary energy source from glucose to ketones, compounds produced in the liver from fat metabolism. This state of nutritional ketosis typically occurs when carbohydrate intake is restricted to 20-50 grams per day, though the exact threshold varies based on individual factors such as muscle mass, insulin sensitivity, and physical activity.

Participants will receive nutritional guidance for the ketogenic diet in a virtual setting via both synchronous and asynchronous engagement including group telehealth sessions, dietary education guides/food lists, quantitative sample meals plans and ongoing messaging capacity with the clinical team for the duration of the dietary intervention.

Behavioral: Carnivore (Lion) Diet

The carnivore (lion) diet is a more restrictive form of a ketogenic diet that is intended as an elimination dietary protocol composed exclusively of ruminant meats (beef, lamb, bison, venison, goat, moose, elk), salt, and water. A broader carnivore diet includes more animal foods such as additional meats, fish, eggs, and some dairy. It excludes, however, all plant foods including vegetables, fruits, grains, legumes, nuts, seeds, or plant-derived oils.

Participants will receive nutritional guidance for the carnivore (lion) and the broader carnivore diet in a virtual setting via both synchronous and asynchronous engagement including group telehealth sessions, dietary education guides/food lists, quantitative sample meals plans and ongoing messaging capacity with the clinical team for the duration of the dietary intervention.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in health-related quality of life measured using the 36-Item Short Form Health Survey (SF-36)
Time Frame: From baseline to 24 weeks
The SF-36 consists of 8 subscales including: physical functioning, role limitations due to physical health (physical role functioning), role limitations due to emotional problems (emotional role functioning), vitality, mental health, social role functioning, bodily pain and general health. Scores for each subscale will be on a 0-100 scale with higher scores generally reflecting better health or less functional impairment for that respective subscale.
From baseline to 24 weeks
Change in health-related quality of life measured using the 36-Item Short Form Health Survey (SF-36)
Time Frame: From baseline to 12 weeks
The SF-36 consists of 8 subscales including: physical functioning, role limitations due to physical health (physical role functioning), role limitations due to emotional problems (emotional role functioning), vitality, mental health, social role functioning, bodily pain and general health. Scores for each subscale will be on a 0-100 scale with higher scores generally reflecting better health or less functional impairment for that respective subscale.
From baseline to 12 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Rheumatoid Arthritis Disease Activity Index-5 Questionnaire (RADAI-5)
Time Frame: From baseline to 12 and 24 weeks

RADAI-5 is a 5-item questionnaire designed to assess rheumatoid arthritis symptomatic activity. Scores for each item are on a 0-10 scale. Higher scores indicate worse outcome/symptoms.

**RA only**
From baseline to 12 and 24 weeks
Change in Routine Assessment of Patient Index Data (RAPID-3)
Time Frame: From baseline to 12 and 24 weeks
RAPID-3 is a questionnaire used to monitor rheumatoid arthritis symptoms and disease activity by measuring a participant's functional status, pain, and overall perception of health. Scores range from 0-30; higher scores indicate worse outcome." **RA only**
From baseline to 12 and 24 weeks
Change in Inflammatory Bowel Disease Symptom Inventory - Short Form (IBDSI-SF)
Time Frame: From baseline to 12 and 24 weeks

The IBDSI-SF measures the frequency and severity of IBD related symptoms as well as their interference with overall functioning and daily activities. We are using a version with 23 questions that excludes the bowel complications subscale - questions 24 and 25 related to fistulas given this as an exclusion criteria. 22 of the 23 questions are scored on a 0-4 scale with higher scores reflecting worse outcome/symptoms. 1 question is rated on a 0-2 scale with a higher score reflecting a worse outcome/symptom. Total scores range from 0-90, higher scores indicating worse outcomes.

**IBD only**
From baseline to 12 and 24 weeks
Change in fecal calprotectin
Time Frame: From baseline to 12 and 24 weeks
Fecal calprotectin is a well established biomarker for intestinal inflammation and validated for diagnosis and monitoring of disease activity in patients with IBD. **IBD only**
From baseline to 12 and 24 weeks
Change in immune and inflammatory serology
Time Frame: From baseline to 12 and 24 weeks
Participants will have associated immune and inflammatory serology to include: 1. Total white blood cell count (WBC), 2. Immune cell differential [neutrophils, lymphocytes, monocytes, eosinophils, and basophils] 3. High sensitivity C-reactive protein (hs-CRP), 4. Erythrocyte sedimentation rate (ESR). Each marker can be assessed independently, but the markers collectively are typically associated together in systemic autoimmune disease and are, hence, described collectively here.
From baseline to 12 and 24 weeks
Change in point of care (at-home) blood ketones (beta-hydroxybutyrate)
Time Frame: From baseline to the end of the study intervention at 24 weeks
Participants will collect periodic at-home measurements of blood ketones (beta-hydroxybutyrate) via a provided blood ketone meter. At-home blood ketones will be primarily utilized to assess adherence to prescribed dietary interventions or self implementation of a interventional dietary strategy for participants on the wait-list.
From baseline to the end of the study intervention at 24 weeks
Change in point of care (at-home) blood glucose
Time Frame: From baseline to the end of the study intervention at 24 weeks
Participants will collect periodic at-home measurements of blood glucose via a provided blood glucose meter. At-home blood glucose measurements will be primarily utilized to assess adherence and safety of the prescribed dietary regimens or self implementation of a interventional dietary strategy for participants on the wait-list.
From baseline to the end of the study intervention at 24 weeks

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in body composition (weight and BMI)
Time Frame: From baseline to the end of the study intervention at 24 weeks
Body composition will be assessed periodically via bioelectrical impedance analysis using a provided Omron HBF-514C Body Composition Monitor. The scale will directly measure body weight and this will be self reported by participants in pounds (lbs) or kilograms (kg) depending on scale setting.. These self reported measurements of weight will be aggregated with a baseline self report of height in inches to calculate associated BMI (kg/m^2).
From baseline to the end of the study intervention at 24 weeks
Change in body composition (skeletal muscle mass)
Time Frame: From baseline to the end of the study intervention at 24 weeks
Body composition will be assessed periodically via bioelectrical impedance analysis using a provided Omron HBF-514C Body Composition Monitor. The scale will provide a direct measurement of skeletal muscle mass measured in kilograms (kg).
From baseline to the end of the study intervention at 24 weeks
Change in body composition (body fat percentage)
Time Frame: From baseline to the end of the study intervention at 24 weeks
Body composition will be assessed periodically via bioelectrical impedance analysis using a provided Omron HBF-514C Body Composition Monitor. The scale will provide a direct measurement of skeletal muscle mass measure in kilograms as well as body weight in kilograms. The scale will provide a calculation of body fat percentage based on these measurements).
From baseline to the end of the study intervention at 24 weeks
Change in body composition (visceral fat estimation)
Time Frame: From baseline to the end of the study intervention at 24 weeks
Body composition will be assessed periodically via bioelectrical impedance analysis using a provided Omron HBF-514C Body Composition Monitor. The scale will provide a estimated measurement of visceral fat. This measurement is reported as a unitless proprietary index (range 1-30); higher scores indicate greater visceral adiposity.
From baseline to the end of the study intervention at 24 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Fuller Research Foundation

Collaborators

Resilient Roots: Functional Medicine

Investigators

  • Principal Investigator: Robert D Abbott, MD, Resilient Roots: Functional Medicine

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 17, 2026

Primary Completion (Estimated)

September 1, 2027

Study Completion (Estimated)

September 1, 2027

Study Registration Dates

First Submitted

March 28, 2026

First Submitted That Met QC Criteria

April 6, 2026

First Posted (Actual)

April 13, 2026

Study Record Updates

Last Update Posted (Actual)

April 16, 2026

Last Update Submitted That Met QC Criteria

April 13, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • BB2506RA-104

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

There is not a plan currently share data

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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