A drink with sugar, a little protein, and a tiny bit of fat after a workout helps muscles recover energy, but not quite as well as a drink with just sugar.
Scientific Claim
Postexercise ingestion of a carbohydrate-protein-fat supplement (0.75 g/kg carbohydrate + 0.1 g/kg protein + 0.02 g/kg fat) increases muscle glycogen resynthesis by approximately 24.6 mmol·kg dry muscle⁻¹·h⁻¹ in trained endurance athletes, which is significantly higher than placebo but lower than carbohydrate-only supplementation.
Original Statement
“Both of these trials resulted in increased glycogen resynthesis (37.2 vs. 24.6 mmol ⋅ kg dry muscle⁻¹ ⋅ h⁻¹, CHO vs. CHO-Pro-Fat, respectively) compared with Pl (7.5 mmol ⋅ kg dry muscle⁻¹ ⋅ h⁻¹); P < 0.001”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design cannot support claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The abstract implies a causal comparison between supplements but lacks confirmation of randomization or blinding. The observed difference is an association, not proven causation.
More Accurate Statement
“Postexercise ingestion of a carbohydrate-protein-fat supplement (0.75 g/kg carbohydrate + 0.1 g/kg protein + 0.02 g/kg fat) is associated with a lower rate of muscle glycogen resynthesis (approximately 24.6 mmol·kg dry muscle⁻¹·h⁻¹) compared to carbohydrate-only supplementation (37.2 mmol·kg dry muscle⁻¹·h⁻¹) in trained endurance athletes.”
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Systematic Review & Meta-AnalysisLevel 1aWhether adding protein and fat to postexercise carbohydrate reduces glycogen resynthesis compared to carbohydrate alone across multiple studies.
Whether adding protein and fat to postexercise carbohydrate reduces glycogen resynthesis compared to carbohydrate alone across multiple studies.
What This Would Prove
Whether adding protein and fat to postexercise carbohydrate reduces glycogen resynthesis compared to carbohydrate alone across multiple studies.
Ideal Study Design
A meta-analysis of 15+ crossover RCTs comparing isoenergetic carbohydrate-only vs. carbohydrate-protein-fat supplements (0.75–1.0 g/kg CHO, 0.1–0.2 g/kg Pro, ≤0.03 g/kg Fat) in endurance athletes, with muscle biopsy-measured glycogen resynthesis over 4h as primary outcome.
Limitation: Cannot determine optimal protein/fat ratios or long-term effects.
Randomized Controlled TrialLevel 1bCausal effect of macronutrient composition (CHO vs. CHO-Pro-Fat) on glycogen resynthesis rate.
Causal effect of macronutrient composition (CHO vs. CHO-Pro-Fat) on glycogen resynthesis rate.
What This Would Prove
Causal effect of macronutrient composition (CHO vs. CHO-Pro-Fat) on glycogen resynthesis rate.
Ideal Study Design
A double-blind, randomized, crossover RCT with 25+ trained endurance athletes, each receiving 1) 1.0 g/kg CHO, 2) 0.75 g/kg CHO + 0.1 g/kg Pro + 0.02 g/kg Fat, and 3) placebo, in random order, with muscle biopsies at 0h and 4h postexercise to measure glycogen resynthesis.
Limitation: Limited to acute effects; does not reflect real-world dietary patterns.
Prospective Cohort StudyLevel 2bLong-term association between habitual postexercise CHO-Pro-Fat intake and glycogen storage efficiency in endurance athletes.
Long-term association between habitual postexercise CHO-Pro-Fat intake and glycogen storage efficiency in endurance athletes.
What This Would Prove
Long-term association between habitual postexercise CHO-Pro-Fat intake and glycogen storage efficiency in endurance athletes.
Ideal Study Design
A 6-month prospective cohort of 80+ endurance athletes tracking postexercise supplement composition (CHO-only vs. CHO-Pro-Fat) via food diaries and measuring quarterly muscle glycogen via biopsy, controlling for training load and energy intake.
Limitation: Cannot isolate macronutrient effects from overall diet or recovery behaviors.
Evidence from Studies
Supporting (0)
Contradicting (1)
Postexercise protein-carbohydrate and carbohydrate supplements increase muscle glycogen in men and women
The study gave athletes a drink with carbs, protein, and fat after exercise and found it helped refill muscle energy, but not as much as a drink with just carbs — which is exactly what the claim says.