Time-restricted Eating and High-intensity Interval Training After Gestational Diabetes (TRE-HIITmoms)

Time-restricted Eating and High-intensity Interval Training After Gestational Diabetes (TRE-HIIT Moms)

This trial will recruit participants who had gestational diabetes in their most previous pregnancy. Participants will be randomly allocated into two groups: one intervention group and one control group 6-12 weeks after giving birth. The intervention group will undergo an 8-week supervised intervention consisting of time-restricted eating and endurance exercise training with moderate-to-high intensity. The investigators will assess cardiorespiratory fitness, body composition, and other markers of cardiovascular and metabolic health before and after the 8 weeks. Additionally, the participants in the intervention group will be encouraged to continue exercising and eating time restricted after the supervised period and follow them up by telephone until one year from the baseline visit. The investigators will measure the same outcomes at the follow-up as on the previous two test points.

Study Overview

• Status: Not yet recruiting
• Conditions: Gestational Diabetes Mellitus With Baby Delivered
• Intervention / Treatment: Behavioral: Time-restricted eating and exercise

Detailed Description

TREHIIT Moms is a randomised, controlled trial with two parallel groups. To be eligible for the trial, the participants need to have had gestational diabetes in their most previous pregnancy and be 6-12 weeks postpartum at inclusion. Participants will be randomly allocated to intervention or control (1:1). The intervention consist of time-restricted eating and endurance exercise. Time-restricted eating implies restricting energy intake to a maximum 10-hour time window daily. The exercise training will be supervised and consist of 2-4 weekly sessions of moderate-to-high intensity exercise. After the supervised period, the participants will continue high-intensity exercise and time-restricted eating at home, with follow-up from the researchers until 1 year from baseline.

The investigators will assess cardiometabolic health outcomes and psychological well-being at baseline, after 8 weeks, and 1 year. Human milk samples will be collected at baseline and 8 weeks and stored for future exploratory analyses of milk composition. The specific analytes and analytical methods will be determined in subsequent exploratory studies and are not prespecified trial outcomes

• Study Type: Interventional
• Enrollment (Estimated): 56
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Trine Moholdt, PhD; Phone Number: +4797098594; Email: trine.moholdt@ntnu.no
• Study Contact Backup: Name: Beathe Sitter, PhD; Phone Number: +4799024180; Email: beathe.sitter@ntnu.no

Study Locations

• Norway
  • Trondheim, Norway, 7491
    • Department of Circulation and Medical Imaging
    • Principal Investigator: Trine Moholdt, PhD
    • Contact: Trine Moholdt, PhD; Phone Number: +4797098594; Email: trine.moholdt@ntnu.no
    • Contact: Beathe Sitter, PhD; Phone Number: +4799024180; Email: beathe.sitter@ntnu.no

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Gestational diabetes mellitus in most recent pregnancy
• Within 6-12 weeks postpartum
• Understands oral and written Norwegian or English
• Able to walk or run on a treadmill or ride a bike for at least 60 minutes
• Living in the Trondheim area

Exclusion Criteria:

• Pregnant or trying to become pregnant
• Diagnosed with type 1 or type 2 diabetes
• Diagnosed with cardiovascular disease
• Have a history of eating disorders (anorexia, bulimia, or binge eating disorder)
• Habitual eating window of less than 12 hours/day
• Engaging in regular high-intensity endurance training (once per week or more)
• Intention of starting an exercise programme and/or a dietary strategy within the study period
• Shift work that includes night shifts
• Bariatric surgery
• Any other reason which, according to the researchers, makes the potential participant ineligible

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention; Time-restricted eating and high-intensity interval training	Behavioral: Time-restricted eating and exercise; The intervention is a combination of time-restricted eating and endurance exercise training. Time-restricted eating implies that the participants will be asked to limit their energy intake to a maximum 10-hour time window daily. The endurance exercise programme consists of 2-4 weekly supervised exercise sessions for 8 weeks. Thereafter, the participants will continue exercising unsupervised with weekly follow-up from researchers.; Other Names: Exercise; Diet
No Intervention: Control; No intervention administered

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak oxygen uptake	Direct measurement of oxygen uptake during graded maximal exercise test to exhaustion	From baseline to after 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak oxygen uptake	Direct measurement of oxygen uptake during graded maximal exercise test to exhaustion	From baseline to after 12 months
Body mass	Estimated by bioimpedance scale	From baseline to after 8 weeks
Body mass	Estimated by bioimpedance scale	From baseline to after 12 months
Fat mass	Estimated by bioimpedance scale	From baseline to after 8 weeks
Fat mass	Estimated by bioimpedance scale	From baseline to after 12 months
Muscle mass	Estimated by bioimpedance scale	From baseline to after 8 weeks
Muscle mass	Estimated by bioimpedance scale	From baseline to after 12 months
Visceral fat area	Estimated by bioimpedance scale	From baseline to after 8 weeks
Visceral fat area	Estimated by bioimpedance scale	From baseline to after 12 months
Bone mass	Estimated by bioimpedance scale	From baseline to after 8 weeks
Bone mass	Estimated by bioimpedance scale	From baseline to after 12 months
Waist circumference	Measured by measuring tape at the level of the umbilicus	From baseline to after 8 weeks
Waist circumference	Measured by measuring tape at the level of the umbilicus	From baseline to after 12 months
Systolic blood pressure	Measured by automatic blood pressure cuff	From baseline to after 8 weeks
Systolic blood pressure	Measured by automatic blood pressure cuff	From baseline to after 12 months
Diastolic blood pressure	Measured by automatic blood pressure cuff	From baseline to after 8 weeks
Diastolic blood pressure	Measured by automatic blood pressure cuff	From baseline to after 12 months
Resting heart rate	Measured by automatic blood pressure cuff	From baseline to after 8 weeks
Resting heart rate	Measured by automatic blood pressure cuff	From baseline to after 12 months
Blood cholesterol	Venous blood sampling	From baseline to after 8 weeks
Blood cholesterol	Venous blood sampling	From baseline to after 12 months
LDL cholesterol	Venous blood sampling	From baseline to after 8 weeks
LDL cholesterol	Venous blood sampling	From baseline to after 12 months
HDL cholesterol	Venous blood sampling	From baseline to after 8 weeks
HDL cholesterol	Venous blood sampling	From baseline to after 12 months
Triglycerides	Venous blood sampling	From baseline to after 8 weeks
Triglycerides	Venous blood sampling	From baseline to after 12 months
Fasting glucose	Venous blood sampling	From baseline to after 8 weeks
Fasting glucose	Venous blood sampling	From baseline to after 12 months
Insulin C-peptide	Venous blood sampling	From baseline to after 8 weeks
Insulin C-peptide	Venous blood sampling	From baseline to after 12 months
Plasma glucose after oral glucose tolerance test	Venous blood sampling 120 minutes after ingesting 75 gram glucose	From baseline to after 8 weeks
Plasma glucose after oral glucose tolerance test	Venous blood sampling 120 minutes after ingesting 75 gram glucose	From baseline to after 12 months
Dietary intake	Self-reported dietary intake using electronic application	From baseline to after 8 weeks
Dietary intake	Self-reported dietary intake using electronic application	From baseline to after 12 months
Mean Daily Minutes of Moderate-to-Vigorous Physical Activity Measured by ActiGraph Accelerometer	Participants will wear an ActiGraph accelerometer for 7 consecutive days. Moderate-to-vigorous physical activity will be determined using prespecified accelerometer count thresholds. For each participant, the total number of minutes classified as moderate-to-vigorous physical activity will be calculated for each valid wear day and averaged across all valid wear days. The reported value will be mean minutes of moderate-to-vigorous physical activity per day. A valid day will be defined as at least 10 hours of accelerometer wear, and participants must have at least 4 valid days to be included in the analysis.	From baseline to after 8 weeks
Mean Daily Minutes of Moderate-to-Vigorous Physical Activity Measured by ActiGraph Accelerometer	Participants will wear an ActiGraph accelerometer for 7 consecutive days. Moderate-to-vigorous physical activity will be determined using prespecified accelerometer count thresholds. For each participant, the total number of minutes classified as moderate-to-vigorous physical activity will be calculated for each valid wear day and averaged across all valid wear days. The reported value will be mean minutes of moderate-to-vigorous physical activity per day. A valid day will be defined as at least 10 hours of accelerometer wear, and participants must have at least 4 valid days to be included in the analysis.	From baseline to after 12 months
Self-reported physical activity	International Physical Activity Questionnaire	From baseline to after 8 weeks
Self-reported physical activity	International Physical Activity Questionnaire	From baseline to after 12 months
Psychological wellbeing	World Health Organization Five Well-Being Index (WHO-5). The World Health Organization Five Well-Being Index (WHO-5) is a 5-item self-report questionnaire assessing subjective psychological well-being over the previous 2 weeks. Raw scores are transformed to a scale ranging from 0 to 100 by multiplying the total raw score by 4. Higher scores indicate better well-being.	From baseline to after 8 weeks
Psychological wellbeing	World Health Organization Five Well-Being Index (WHO-5). The World Health Organization Five Well-Being Index (WHO-5) is a 5-item self-report questionnaire assessing subjective psychological well-being over the previous 2 weeks. Raw scores are transformed to a scale ranging from 0 to 100 by multiplying the total raw score by 4. Higher scores indicate better well-being.	From baseline to after 12 months
Sleep quality	Pittsburgh Sleep Quality Index questionnaire global score. The Pittsburgh Sleep Quality Index (PSQI) is a 19-item self-report questionnaire that assesses sleep quality over the previous month. The global PSQI score ranges from 0 to 21, with higher scores indicating worse sleep quality.	From baseline to after 8 weeks
Sleep quality	Pittsburgh Sleep Quality Index questionnaire global score. The Pittsburgh Sleep Quality Index (PSQI) is a 19-item self-report questionnaire that assesses sleep quality over the previous month. The global PSQI score ranges from 0 to 21, with higher scores indicating worse sleep quality.	From baseline to after 12 months
Depression	The Edinburgh Postnatal Depression Scale (EPDS) global score. The Edinburgh Postnatal Depression Scale is a 10-item self-report questionnaire that assesses symptoms of depression over the previous 7 days. The total score ranges from 0 to 30, with higher scores indicating more severe depressive symptoms.	From baseline to 8 weeks
Depression	The Edinburgh Postnatal Depression Scale (EPDS) global score. The Edinburgh Postnatal Depression Scale is a 10-item self-report questionnaire that assesses symptoms of depression over the previous 7 days. The total score ranges from 0 to 30, with higher scores indicating more severe depressive symptoms.	From baseline to after 12 months
Anxiety	Generalised anxiety disorder questionnaire (GAD-7) total score. The Generalized Anxiety Disorder 7-Item (GAD-7) is a 7-item self-report questionnaire that assesses symptoms of generalized anxiety over the previous 2 weeks. The total score ranges from 0 to 21, with higher scores indicating more severe anxiety symptoms.	From baseline to after 8 weeks
Anxiety	Generalised anxiety disorder questionnaire (GAD-7) total score. The Generalized Anxiety Disorder 7-Item (GAD-7) is a 7-item self-report questionnaire that assesses symptoms of generalized anxiety over the previous 2 weeks. The total score ranges from 0 to 21, with higher scores indicating more severe anxiety symptoms.	From baseline to after 12 months
Type 2 diabetes mellitus diagnosis	Participant-reported or measurement of HbA1c of 48 mmol/mol or above	During the 12-month follow-up
Mean Daily Step Count Measured by ActiGraph Accelerometer	Participants will wear an ActiGraph accelerometer for 7 consecutive days. The number of steps recorded on each valid wear day will be averaged across all valid wear days for each participant. A valid day will be defined as at least 10 hours of accelerometer wear, and at least 4 valid days will be required.	From baseline to after 8 weeks
Mean Daily Sedentary Time Measured by ActiGraph Accelerometer	Participants will wear an ActiGraph accelerometer for 7 consecutive days. Sedentary time will be identified using a prespecified accelerometer count threshold. Minutes classified as sedentary will be calculated for each valid wear day and averaged across all valid wear days for each participant. A valid day will be defined as at least 10 hours of accelerometer wear, and at least 4 valid days will be required.	At baseline and after 8 weeks
Mean Daily Step Count Measured by ActiGraph Accelerometer	Participants will wear an ActiGraph accelerometer for 7 consecutive days. The number of steps recorded on each valid wear day will be averaged across all valid wear days for each participant. A valid day will be defined as at least 10 hours of accelerometer wear, and at least 4 valid days will be required.	From baseline to after 12 months
Mean Daily Sedentary Time Measured by ActiGraph Accelerometer	Participants will wear an ActiGraph accelerometer for 7 consecutive days. Sedentary time will be identified using a prespecified accelerometer count threshold. Minutes classified as sedentary will be calculated for each valid wear day and averaged across all valid wear days for each participant. A valid day will be defined as at least 10 hours of accelerometer wear, and at least 4 valid days will be required.	From baseline to after 12 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Infant feeding method	Infant feeding practices will be assessed using a study questionnaire. Feeding method will be categorized as exclusive breastfeeding, partial breastfeeding, exclusive formula feeding, or complementary feeding, as appropriate for the infant's age. The number and proportion of infants in each feeding category will be reported at each assessment.	Baseline, 8 weeks, and after 12 months
Adherence to time-restricted eating	Time-frame for daily energy intake, reported as average and percentage of participants who adhere to < 10 hours daily energy intake window	Baseline, after 8 weeks and after 12 months
Adherence to exercise training	Number of completed sessions, recorded using an electronic application	During the 8-week intervention and during the 12-month follow-up
Perception of intervention and follow-up	Qualitative interviews with selected participants to explore barriers and motivators	After 12 months

Collaborators and Investigators

• Sponsor: Norwegian University of Science and Technology
• Collaborators: St. Olavs Hospital
• Investigators: Principal Investigator: Trine Moholdt, PhD, Norwegian University of Science and Technology

Study record dates

Study Major Dates

• Study Start (Estimated): August 15, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): January 1, 2029

Study Registration Dates

• First Submitted: July 3, 2026
• First Submitted That Met QC Criteria: August 17, 2026
• First Posted (Actual): August 20, 2026

Study Record Updates

• Last Update Posted (Actual): August 20, 2026
• Last Update Submitted That Met QC Criteria: August 17, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Exercise; High-intensity interval training; Time-restricted eating
• Additional Relevant MeSH Terms: Behavior; Feeding Behavior; Fasting; Motor Activity; Intermittent Fasting; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena; Nutritional Physiological Phenomena; Exercise; Diet
• Other Study ID Numbers: 987380

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

We will make de-identified individual participant data (IPD) collected in the study available to other researchers. We will upload a data set in an open access repository.

We will only share IPD that cannot be used to identify individuals.

• IPD Sharing Time Frame: Data will become available at the time of publication of the results from the study

IPD Sharing Access Criteria

De-identified individual participant data underlying published results will be available upon reasonable request following publication of the primary study results.

Requests must be accompanied by a research proposal and statistical analysis plan. Requests will be reviewed by the Principal Investigator and study investigators for scientific merit, feasibility, consistency with participant consent, and compliance with applicable ethical and legal requirements. Approved researchers will be required to sign a data sharing agreement.

Only de-identified data will be shared. Data may be modified as necessary to minimize the risk of participant re-identification while preserving scientific utility.

• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No