Time-Restricted Feeding on Cardiovascular Health Effects

Study Design and Participants This intervention study was conducted as a randomized controlled trial (RCT) aimed at investigating the effects of time-restricted feeding (TRF) on cardiovascular health markers among overweight male university students in Shenzhen, China. The study recruited male university students aged between 18 and 24 years, with a Body Mass Index (BMI) ranging from 24 to less than 28. All participants were free from severe psychiatric illnesses, metabolic syndrome, diabetes, alcoholic fatty liver disease, hyperthyroidism, or hypothyroidism. Inclusion criteria required participants to be non-smokers, not currently on any diet pills, and have no history of cardiovascular or metabolic diseases.

Randomization and Intervention Fifty eligible participants were randomly assigned to either the intervention group (n=25) or the control group (n=25). The intervention group underwent a 6-hour daily TRF from noon to 6 P.M., while the control group did not participate in TRF but maintained their usual eating patterns. No restrictions were placed on the type or quantity of food consumed by participants in either group.

Data Collection and Measures Body Composition and Anthropometry: Measurements included body mass index, body fat percentage, muscle mass, hydration levels, protein content, and visceral fat, all assessed using a bioelectrical impedance analysis scale (Mi Body Composition Scale 2 by Huami Technology). Waist circumference was manually measured by experienced nurses using a tape measure.

Blood Pressure and Heart Rate: These vital signs were monitored using an arm cuff electronic blood pressure monitor (Panasonic EW3153), with the arm positioned at heart level to ensure accuracy. Measurements were taken after at least five minutes of seated rest.

Nutritional Intake Although time-restricted feeding interventions do not usually change the content or quantity of dietary intake, the total daily intakes of energy, fat, protein, carbohydrate, cholesterol, and fibre were calculated using the Nutritionist Pro food analysis program. This was used to determine possible changes in the subjects' dietary composition as a result of the intervention.

Compliance and Ethical Considerations The study protocol was approved by the Ethics Committee of the Seventh Affiliated Hospital of Sun Yat-sen University (Shenzhen), with the approval number KY-2022-101-01. All data were handled confidentially, and measures were taken to ensure high adherence and minimal loss to follow-up.

Statistical Analysis Descriptive statistics such as range, mean, standard deviation, and percentages were used to describe the sample characteristics. To compare differences, the change from baseline levels was assessed to account for initial variability, employing an independent samples t-test for the analysis.


Eligibility Criteria:
Inclusion Criteria:

* Subjects were able to provide signed and dated written informed consent.
* Subjects are male undergraduates aged 18-24 years old.
* BMI between 24 and 28.
* Normal sleep duration, usually between 7-9 hours per day.
* Stable sleep habits, typically going to bed around midnight (±1 hour).

Exclusion Criteria:

* Inability to comply with the time-limited diet plan.
* Experiencing hypoglycemic reactions during the time-limited diet program.
* Presence of metabolic diseases such as diabetes.
* Participation in high-intensity physical training for more than 5 hours per week.
* Extreme chronotypes, as indicated by scores ≤30 or ≥70 on the Morning and Evening Questionnaire Self-Assessment Scales (MEQ-SA).
* Severe weight instability, defined as weight gain or loss of more than 5 kg in the 3 months prior to the study.
* Severe food allergy or intolerance.
* Participation in another medical study within 6 months prior to the first study visit.