Influence of a high-fat vs. carbohydrate-rich low-glycemic vs. carbohydrate-rich high-glycemic diet on metabolic regulation in male endurance athletes

Influence of a high-fat vs. carbohydrate-rich low-glycemic vs. carbohydrate-rich high-glycemic diet on metabolic regulation in male endurance athletes - Glyx Study

Status

Active, not recruiting

Phases

Phase 3

Study type

Interventional

Source

DRKS

Registry ID

DRKS00015521

Enrollment

Registered

2018-09-13

Start date

2017-11-01

Completion date

Unknown

Last updated

2025-04-07

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Metabolic adaptation (fat and carbohydrate metabolism) in healthy male endurance athletes

Interventions

Group 1: - U-1: screening: Testing of inclusion and exclusion criteria, determination of VO2peak and the aerobic threshold (Lactate Threshold [LT]) in the cycling test (morning, fasting, resting state

Eligibility

Sex/Gender

Male

Age

18 Years to 50 Years

Inclusion criteria

Inclusion criteria: - Age between 18-50 years - Performance of endurance sports (running, cycling, playing sports), which require a basic endurance (3 - 5 units/week, VO2max > 55 mL/kg/min) - stable weight and nutritional behavior (mixed diet) - willing to be randomized - no contraindications vs. physical activity according to the guidelines of the ACSM

Exclusion criteria

Exclusion criteria: - exessive endurance sport (> 5 units / wk) - maligne diseases in the past 5 years - cardiac disease (eg, chronic heart disease, arrhythmia, valvular heart disease, arthritis, etc.) - arterial hypertension (RRsyst> 200 mmHg and / or RRdiast> 105 mmHg) at rest - presence of Insulin-Dependent Diabetes Mellitus (IDDM) - presence of a lipid metabolism disorder - regular use of medication

Design outcomes

Primary

Measure	Time frame
- Respiratory quotient (RQ) at rest (fasten in the morning) - RQ in a 10-minute aerobic test (LT + 20 watts) - Respiratory quotient under load (VT, RCP) - Lactate thresholds (VT, IAS) - VO2peak or Wattmax each per kg of body weight - resting metabolism - Glucose at rest (fasten) under exercise - Fat mass determined by BIA (under standard conditions) - Rate of Perceived Exertionn (RPE) using the Borg scale - VAS score for general mood, GIT discomfort and exercise tolerance - Measurement: U1 (screening), U2 (initial examination), U3 (interim examination) and U4 (final examination) - *Measurement only at U2 (initial examination), U3 (intermediate examination) and U4 (final examination)	—

Measure

Time frame

- *Respiratory quotient (RQ) at rest (fasten in the morning) - *RQ in a 10-minute aerobic test (LT + 20 watts) - Respiratory quotient under load (VT, RCP) - Lactate thresholds (VT, IAS) - VO2peak or Wattmax each per kg of body weight - *resting metabolism - Glucose at rest (fasten) under exercise - Fat mass determined by BIA (under standard conditions) - Rate of Perceived Exertionn (RPE) using the Borg scale - *VAS score for general mood, GIT discomfort and exercise tolerance - Measurement: U1 (screening), U2 (initial examination), U3 (interim examination) and U4 (final examination) - *Measurement only at U2 (initial examination), U3 (intermediate examination) and U4 (final examination)

—

Secondary

Measure	Time frame
Exploratory assessment in of physiological parameters (maximum oxygen uptake (V?O2 peak), RER and submaximal metabolic inflection points (lactate threshold 1 [LT1] and lactate threshold 2 [LT2]) during incremental cycling test until exhaustion after ingestion of a carbohydrate-rich, low glycaemic test meal within 1 week after the final examination (study arm 1 and 2)	—

Countries

Germany

Contacts

Public ContactDenise Zdzieblik

Institut für Sport und SportwissenschaftUniversität Freiburg

denise.zdzieblik@sport.uni-freiburg.de0761 20354087

Outcome results

None listed

Source: DRKS (via WHO ICTRP) · Data processed: Feb 4, 2026