Early Time-Restricted Eating in Young Judo Athletes

Effects of a 5-Month Early Time-Restricted Eating Protocol on Body Composition, Muscle Damage Biomarkers, Competitive Anxiety, and Self-Confidence in Highly Trained Young Judo Athletes: A Randomized Controlled Trial

This study investigates the effects of a 5-month early time-restricted eating (e-TRE) intervention on body composition, muscle damage biomarkers, and psychological variables in highly trained young male judo athletes. One hundred participants were randomly assigned to either an e-TRE group or a control group. The e-TRE group followed a 16:8 fasting protocol (07:00-15:00 eating window) while maintaining their usual training program, whereas the control group maintained habitual dietary patterns. Outcomes included changes in body composition (BMI, body fat, skeletal muscle mass), muscle damage biomarkers (CK, LDH, ASAT, ALAT, uric acid, CRP, total bilirubin), and psychological measures (cognitive anxiety, somatic anxiety, and self-confidence assessed using CSAI-2). Measurements were taken at baseline and after the intervention period. The aim of the study is to determine whether e-TRE can improve physiological recovery and psychological readiness in combat sport athletes without negatively affecting performance-related variables.

This study was designed to evaluate the effects of a 5-month early time-restricted eating (e-TRE) intervention on physiological and psychological outcomes in highly trained young male judo athletes. The study included 100 participants recruited from competitive judo teams in Tunisia. Participants were randomly assigned to either an e-TRE group or a control group in a 1:1 ratio.

The e-TRE group followed a structured 16:8 time-restricted eating protocol, consuming all daily energy intake within an 8-hour window from 07:00 to 15:00, followed by a 16-hour fasting period. During fasting hours, only non-caloric beverages were permitted. The control group maintained their habitual dietary intake and meal timing without any modifications. Both groups continued their regular judo training program, consisting of 5-6 training sessions per week, including technical drills, sparring (randori), and strength and conditioning exercises.

Anthropometric and biochemical measurements were collected at baseline (T0) and after the 5-month intervention (T1). Psychological assessments were conducted before monthly competitions throughout the study period. Blood samples were collected under standardized resting conditions and analyzed using validated enzymatic and immunoassay techniques.

Participants were required to meet strict inclusion criteria, including age 18-26 years, male sex, at least 3 years of judo training experience, and absence of metabolic, psychiatric, or chronic diseases. Exclusion criteria included use of medications or supplements affecting metabolism, prior experience with intermittent fasting, and conditions that could affect training or biomarker outcomes.

The study was approved by the Ethics Committee of the Higher Institute of Sport and Physical Education of Ksar Said, University of Manouba, Tunisia (approval No. 0171823; organization's unique protocol ID: ISSEP-2026-023) and was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants prior to enrollment

Statistical analyses included repeated-measures ANOVA to assess group × time effects, with significance set at p < 0.05. Effect sizes were calculated using partial eta squared (η²).

Inclusion Criteria:

• aged 19-26 years;
• male judo players; c) with at least 3 years of judo training experience;
• engaged in judo training 5-6 days per week; e) healthy, with no known chronic illnesses or conditions affecting metabolism, mental health, or physical performance;
• willing to adhere to a 16:8 e-TRE protocol for the 5-month study period;
• non-smokers, as smoking may affect anxiety levels and cardiovascular health;
• not using any performance-enhancing drugs or supplements that could interfere with the study's measurements.

Exclusion Criteria:

• current musculoskeletal injuries or conditions that could limit participation in training or affect muscle damage biomarkers;
• diagnosed psychiatric disorders or current treatment for anxiety or mood disorders, as these could interfere with psychological assessments;
• use of medications affecting metabolism, muscle recovery, or psychological state (e.g., corticosteroids, antidepressants);
• prior experience with time-restricted eating or intermittent fasting within the past year, as prior adaptation could impact study outcomes;
• dietary restrictions or practices (e.g., vegan or keto diet) that could affect nutrient intake or metabolic markers;
• diagnosed sleep disorders or irregular sleep patterns, as sleep quality could impact both muscle recovery and psychological parameters;
• inability to commit to the structured training program over the study period.