Instead of telling these players to eat more protein, nutritionists should focus on getting them to eat more carbs — especially on game days — because they’re not eating enough total calories.
Scientific Claim
Sports nutritionists should prioritize increasing carbohydrate intake over emphasizing high protein consumption to meet the energy demands of professional female football players, based on observed energy deficits and carbohydrate intake patterns.
Original Statement
“To fuel these requirements, sports nutritionists should consider shifting the players’ focus towards prioritizing adequate carbohydrate intakes, rather than emphasizing high protein consumption.”
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 uses prescriptive language ('should consider shifting') implying a recommendation based on proven efficacy, but the study is observational and did not test any intervention. This overstates the evidence.
More Accurate Statement
“Professional female football players exhibit low energy intake relative to expenditure and higher carbohydrate intake on high-demand days, suggesting that sports nutritionists may consider prioritizing carbohydrate intake over high protein consumption to better align with energy needs — though this remains untested.”
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.
Randomized Controlled TrialLevel 1bWhether shifting focus from protein to carbohydrate intake improves energy balance, performance, or recovery in female footballers.
Whether shifting focus from protein to carbohydrate intake improves energy balance, performance, or recovery in female footballers.
What This Would Prove
Whether shifting focus from protein to carbohydrate intake improves energy balance, performance, or recovery in female footballers.
Ideal Study Design
A double-blind RCT of 60 professional female football players randomized to either: (1) standard high-protein nutrition advice (2.0 g/kg protein, 5 g/kg carbs) or (2) carbohydrate-focused advice (1.6 g/kg protein, 6.5 g/kg carbs) for 12 weeks, measuring energy balance (doubly labeled water), body composition (DXA), training performance, and menstrual function.
Limitation: Cannot determine long-term sustainability or effects on bone health.
Prospective Cohort StudyLevel 2bWhether teams that adopt carbohydrate-focused nutrition strategies show improved performance or reduced injury rates over a season.
Whether teams that adopt carbohydrate-focused nutrition strategies show improved performance or reduced injury rates over a season.
What This Would Prove
Whether teams that adopt carbohydrate-focused nutrition strategies show improved performance or reduced injury rates over a season.
Ideal Study Design
A 12-month prospective cohort comparing 10+ teams: 5 implementing carbohydrate-focused nutrition (target: 6 g/kg on match days, protein ≤1.7 g/kg) vs. 5 maintaining protein-focused advice, tracking performance metrics, injury incidence, and energy availability.
Limitation: Cannot control for coaching influence, player compliance, or other confounders.
Case-Control StudyLevel 3Whether athletes with higher carbohydrate intake (≥5.5 g/kg) have better energy availability or fewer metabolic disruptions than those with lower intake.
Whether athletes with higher carbohydrate intake (≥5.5 g/kg) have better energy availability or fewer metabolic disruptions than those with lower intake.
What This Would Prove
Whether athletes with higher carbohydrate intake (≥5.5 g/kg) have better energy availability or fewer metabolic disruptions than those with lower intake.
Ideal Study Design
A case-control study comparing 30 female footballers with chronic energy deficit (EA <30 kcal/kg FFM) to 30 matched controls with adequate EA, assessing dietary patterns, particularly carbohydrate and protein intake, and hormonal markers (leptin, T3, estradiol).
Limitation: Cannot determine if low carbs caused the deficit or if it’s a consequence.
Evidence from Studies
Supporting (1)
The study found that these female soccer players aren't eating enough carbs to fuel their training, but they're already eating enough protein — so nutritionists should tell them to eat more carbs, not more protein.