NCT07802275

Brief Summary

The goal of this study is to test whether a low-carbohydrate diet (LCD), comparred with a Mediterranean diet (MED) producing similar weight loss, differentially affects fasting and postprandial glucose metabolism in individuals with overweight and dysglycemia. The main questions it aims to answer are:

  • Is oral glucose absorption delayed or reduced after chronic carbohydrate restriction?
  • Is insulin sensitivity differentially affected? Participants will follow 4 weeks of LCD and 4 weeks of MED, in a random order, separated by a 4-week washout. After each intervention, participants will undergo a dual-tracer 75-g oral glucose tolerance test.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
29

participants targeted

Target at below P25 for not_applicable

Timeline
Completed

Started Nov 2019

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

November 1, 2019

Completed
4.4 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

March 30, 2024

Completed
2.4 years until next milestone

Study Completion

Last participant's last visit for all outcomes

August 30, 2026

Completed
1 day until next milestone

First Submitted

Initial submission to the registry

August 31, 2026

Completed
3 days until next milestone

First Posted

Study publicly available on registry

September 3, 2026

Completed
Last Updated

September 3, 2026

Status Verified

August 1, 2026

Enrollment Period

4.4 years

First QC Date

August 31, 2026

Last Update Submit

August 31, 2026

Conditions

PrediabetesObesity & OverweightDiet InterventionsCarbohydrate Metabolism

Keywords

obesityoverweighttype 2 diabeteslow carbohydrate dietmediterranean dietprediabetesketogenic dietimpaired glucose toleranceglucose absorptioninsulin resistanceinsulin sensitivity

Outcome Measures

Primary Outcomes (1)

  • Oral glucose appearance

    Rate of appearance of orally ingested glucose in the systemic circulation

    During the oral glucose tolerance test at the end of each 4-week diet

Secondary Outcomes (2)

  • Endogenous glucose production

    During the oral glucose tolerance test at the end of each 4-week diet

  • Glucose clearance

    During the oral glucose tolerance test at the end of each 4-week diet

Other Outcomes (5)

  • Glucose tolerance

    During the oral glucose tolerance test at the end of each 4-week diet

  • Beta cell function

    During the oral glucose tolerance test at the end of each 4-week diet

  • Insulin sensitivity

    During the oral glucose tolerance test at the end of each 4-week diet

  • +2 more other outcomes

Study Arms (2)

Low-carbohydrate diet

EXPERIMENTAL
Behavioral: Low-carbohydrate diet

Mediterranean diet

ACTIVE COMPARATOR
Behavioral: Mediterranean Diet

Interventions

Low-carbohydrate dietBEHAVIORAL

A 4-week diet providing 20% of total energy from carbohydrates, 55% from fat, and 25% from protein, with an energy restriction of 200-400 kcal/day relative to basal metabolic rate.

Low-carbohydrate diet
Mediterranean DietBEHAVIORAL

A 4-week diet providing 50% of total energy from carbohydrates, 30% from fat, and 20% from protein, with an energy restriction of 200-400 kcal/day relative to basal metabolic rate.

Mediterranean diet

Eligibility Criteria

Age18 Years - 65 Years
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • both females and males
  • age 18-65 years
  • BMI 25-40 kg/m2
  • impaired glucose regulation (defined as fasting plasma glucose 5.6-6.9 mmol/L, 1-h plasma glucose ≥8.6 mmol/L, 2-h plasma glucose 7.8-11.0 mmol/L, or HbA1c 39-47 mmol/mol)

You may not qualify if:

  • Diabetes mellitus
  • Chronic kidney disease
  • Heart failure
  • Severe liver disease
  • Medications known to interfere with carbohydrate metabolism or intestinal nutrient absorption
  • Metabolic surgery

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Laboratory of Metabolism, Nutrition and Atherosclerosis, University of Pisa

Pisa, PI, 56126, Italy

Location

MeSH Terms

Conditions

Prediabetic StateObesityOverweightDiabetes Mellitus, Type 2Glucose IntoleranceInsulin Resistance

Interventions

Diet, Carbohydrate-RestrictedDiet, Mediterranean

Condition Hierarchy (Ancestors)

Diabetes MellitusGlucose Metabolism DisordersMetabolic DiseasesNutritional and Metabolic DiseasesEndocrine System DiseasesOvernutritionNutrition DisordersBody WeightSigns and SymptomsPathological Conditions, Signs and SymptomsHyperglycemiaHyperinsulinism

Intervention Hierarchy (Ancestors)

Diet TherapyNutrition TherapyTherapeuticsDietNutritional Physiological PhenomenaDiet, Food, and NutritionPhysiological PhenomenaDiet, Plant-Based

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
BASIC SCIENCE
Intervention Model
CROSSOVER
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Professor

Study Record Dates

First Submitted

August 31, 2026

First Posted

September 3, 2026

Study Start

November 1, 2019

Primary Completion

March 30, 2024

Study Completion

August 30, 2026

Last Updated

September 3, 2026

Record last verified: 2026-08

Data Sharing

IPD Sharing
Will not share

Confidentiality reasons

Locations

IT(1)