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OpenTrials
Completed

NCT Number: NCT07600138

Effects of Carbohydrates Versus Carbohydrates + Protein on Resistance Training Outcomes

Higher energy and carbohydrate intakes have been hypothesized to enhance resistance training adaptations, yet empirical evidence remains mixed. This study investigated whether supplemental carbohydrate-energy intake improves muscle hypertrophy, strength, and fatigue resistance in resistance-trained men.

Twenty resistance-trained men completed a quasi-randomized, double-blinded, counterbalanced crossover trial. Participants consumed either a daily protein-only supplement (30 g protein, 4 g carbohydrate) or a daily protein-plus-carbohydrate supplement (30 g protein, 54 g carbohydrate) for 8 weeks each, followed by crossover, while continuing their habitual training and diet. Primary outcomes included lean mass (dual-energy x-ray absorptiometry), muscle thickness and cross-sectional area (ultrasound), back squat one-repetition maximum, knee extensor peak torque, and fatigue index.

The carbohydrate-protein supplement produced significantly higher daily energy and carbohydrate intake compared to the protein-only supplement, with no differences in protein intake, fat intake, or training volume. No significant between-condition differences were observed for any outcome. These results suggest that modest increases in carbohydrate-energy intake outside of an energy deficit are unlikely to meaningfully enhance muscle hypertrophy, strength, or fatigue resistance in trained men.

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Key information

Conditions

Muscle Hypertrophy Strength

Age range

18 year–40 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

School of Kinesiology

Auburn, Alabama, 36879-5432, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Male sex
  • Aged 18-40 years
  • BMI not exceeding 35 kg/m²
  • Minimum of two years resistance training experience
  • Resistance training frequency of at least four days per week
  • No known allergy to whey protein supplements

Exclusion criteria

  • Known cardio-metabolic disease (e.g., clinical obesity, diabetes, hypertension, heart disease)
  • Any condition contraindicating participation in resistance training
  • Known allergy to whey protein supplements

Treatment and study plan

CHO

Dietary Supplement

Daily consumption of a whey protein and maltodextrin mixture providing 30 g protein, 54 g carbohydrate, and 2 g fat per 92 g serving for 8 weeks

Other names: Whey protein + CHO

PRO

Dietary Supplement

Daily consumption of a whey protein blend providing 30 g protein, 4 g carbohydrate, and 2 g fat per 39 g serving for 8 weeks.

Other names: Whey protein only

Primary outcomes

  1. Lean mass

    Time frame: Baseline, 8 weeks (mid-point), 16 weeks (post)

    Bone-free lean tissue mass according to Dual-energy X-ray absorptiometry (DXA)

  2. Mid-thigh muscle thickness

    Time frame: Baseline, 8 weeks (mid-point), 16 weeks (post)

    Change in lateral thigh muscle thickness (vastus lateralis and vastus intermedius)

  3. Back Squat One-Repetition Maximum

    Time frame: Baseline, 8 weeks (mid-point), 16 weeks (post)

    Change in back squat 1RM

  4. Knee Extensor Peak Torque

    Time frame: Baseline, 8 weeks (mid-point), 16 weeks (post)

    Change in knee extensor peak torque using isokinetic dynamometry

Sponsors and collaborators

Lead sponsor

Auburn University

Other

Registry information

Acronym: CHO & PRO+CHO

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
May 20, 2026
Registry last updated
May 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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