Comparing Intermittent Fasting, Clean Ketogenic Diet, and Their Combined Effects on Body Composition, Cardiometabolic Markers, and Metabolic Health

June 16, 2026 updated by: Angie MacKewn, The University of Tennessee at Martin
A cross-study analysis combined data from two sequential pre-post intervention studies conducted at the University of Tennessee at Martin, yielding a three-arm design comprising intermittent fasting alone (n = 16), clean ketogenic diet alone (n = 22), and combined clean ketogenic diet with intermittent fasting (n = 41). The clean ketogenic diet restricted carbohydrate intake to 20 grams per day from whole unprocessed sources and eliminated refined sugars, high-fructose corn syrup, and ultra-processed foods.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The intermittent fasting protocol employed a 16:8 time-restricted eating window. Paired-samples t-tests examined within-group pre-to-post changes. One-way analyses of variance with Tukey post-hoc comparisons examined between-group differences in magnitude of change. Effect sizes are reported as Hedges' g for within-group comparisons and eta-squared for between-group comparisons. An independent samples t-test compared glycosylated hemoglobin changes between the intermittent fasting and combined groups. Spearman and Kendall correlations examined associations between fat mass and cardiometabolic change.

Study Type

Interventional

Enrollment (Actual)

79

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 Locations

  • United States
    • Tennessee
      • Martin, Tennessee, United States, 38238
        • University of Tennessee at Martin

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
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

-

Exclusion Criteria:

  • pregnant

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: Other
  • Allocation: Randomized
  • Interventional Model: Single Group Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Clean ketogenic Diet
Participants ate low carb, under 20 g per day
Other: Diet
intervention was either clean keto, intermittent fasting 16:8 schedule or a combination of both
Other Names:
  • Clean Keto, Intermittent fasting
Experimental: Intermittent fasting
Participants went on a 16:8 feeding window
Other: Diet
intervention was either clean keto, intermittent fasting 16:8 schedule or a combination of both
Other Names:
  • Clean Keto, Intermittent fasting
Experimental: Clean keto and IF
Combined Clean keto and intermittent fasting
Other: Diet
intervention was either clean keto, intermittent fasting 16:8 schedule or a combination of both
Other Names:
  • Clean Keto, Intermittent fasting

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Concentration of HDL Cholesterol
Time Frame: Baseline and 30 days
Fasting Blood draw to assess high-density lipoprotein cholesterol levels
Baseline and 30 days
Concentration of Serum Triglycerides
Time Frame: baseline and 30-days
Fasting blood draw to assess serum triglyceride levels
baseline and 30-days
Concentration of Hemoglobin A1c (HbA1c)
Time Frame: Baseline and 30 days
Blood draw to assess HbA1c as a marker of glycemic control
Baseline and 30 days

Collaborators and Investigators

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

Sponsor

The University of Tennessee at Martin

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)

September 15, 2024

Primary Completion (Actual)

December 20, 2024

Study Completion (Actual)

February 15, 2025

Study Registration Dates

First Submitted

June 3, 2026

First Submitted That Met QC Criteria

June 16, 2026

First Posted (Actual)

June 22, 2026

Study Record Updates

Last Update Posted (Actual)

June 22, 2026

Last Update Submitted That Met QC Criteria

June 16, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2021-872-E05-4065/MacK, Ang
  • 22-925-E05-4065/Mack,Ang (Other Identifier: UT Martin)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

we will share all data and instruments, but we don't have a plan for an IPD right now

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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