Effects of Carbohydrates Versus Carbohydrates + Protein on Resistance Training Outcomes

Conditions

• Muscle Hypertrophy
• Strength

Eligibility Criteria

Sex

MALE

Age

18 Years - 40 Years

Healthy Volunteers

Accepted

Interventions

• 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
• 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.

Study Details

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.

Key Dates

Start date

May 12, 2025

Status verified

May 2026

Primary completion

Sep 15, 2025

Completion

Sep 16, 2025

Study Design

Enrollment

25 participants (actual)

Allocation

NON_RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

TREATMENT

Arms

• Experimental: CHO
  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.
• Active Comparator: PRO
  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.

Primary Outcome Measure

Lean mass [ Time Frame: Baseline, 8 weeks (mid-point), 16 weeks (post) ]

Locations (1)

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