According to Gram Research analysis, female rugby athletes who ate double the carbohydrates (6 grams per kilogram of body weight) compared to peers eating moderate amounts (3 grams per kilogram) showed similar strength gains and muscle development over seven weeks, suggesting that maximum carbohydrate intake may not be necessary for female athletes to improve performance during preseason training.
A new study looked at whether female rugby players performed better when eating more carbohydrates during training. Researchers gave one group of athletes double the carbs (6 grams per kilogram of body weight) compared to another group (3 grams per kilogram) over seven weeks. While the higher-carb group had more energy available to their bodies, surprisingly, both groups showed similar improvements in strength and muscle gain. The study suggests that for female athletes, eating more carbs might not be the game-changer many assume, though the research involved only a small number of players.
Key Statistics
A 2026 exploratory study of 13 female rugby athletes found that both high-carbohydrate (6 g·kg⁻¹·day⁻¹) and moderate-carbohydrate (3 g·kg⁻¹·day⁻¹) groups improved bench press strength by approximately 4.6 kilograms over seven weeks of preseason training.
In a 2026 study of female rugby players, the lower-carbohydrate group slept significantly longer on training nights despite having less energy available, suggesting that higher carbohydrate intake does not automatically improve post-training sleep duration.
A 2026 research article examining 13 semiprofessional female rugby athletes found that both groups lost approximately 1.1 kilograms of fat and gained 1.2 kilograms of muscle over seven weeks, regardless of whether they consumed 6 or 3 grams of carbohydrates per kilogram of body weight on training days.
According to a 2026 exploratory study, female rugby athletes in the high-carbohydrate group had 45 calories per kilogram of fat-free mass available daily compared to 30 in the moderate-carbohydrate group, yet this 50% difference in energy availability did not produce significantly better training adaptations.
The Quick Take
- What they studied: Whether eating more carbohydrates helps female rugby athletes build muscle, get stronger, and sleep better during intense training
- Who participated: 13 semiprofessional female rugby union players (7 in the high-carb group, 6 in the regular-carb group) during a 7-week preseason training period
- Key finding: Both groups improved their strength and muscle similarly, even though the high-carb group had significantly more energy available. The lower-carb group actually slept longer on training nights.
- What it means for you: Female athletes shouldn’t assume they automatically need maximum carbohydrates to improve performance. Individual needs vary, and other factors like sleep and overall training matter too. However, this was a small study, so more research is needed before changing nutrition plans.
The Research Details
Researchers divided 13 female rugby players into two groups during a 7-week preseason. One group ate about 6 grams of carbs per kilogram of body weight on training days (roughly double the other group’s 3 grams per kilogram). Both groups ate the same amount of protein to keep that variable consistent. On non-training days, both groups ate whatever they wanted. The researchers carefully measured how much energy each athlete burned during exercise using special wearable devices, then calculated how much energy was actually available to their bodies after accounting for training demands.
Before and after the seven weeks, scientists tested everything: how much weight athletes could lift (squats, bench pulls, and bench presses), how fast they could run a shuttle test, how high they could jump, their body composition (muscle versus fat), blood markers (iron, thyroid function, cholesterol), and sleep quality and duration.
This approach allowed researchers to see whether having more carbohydrates available to the body actually translated into better athletic performance and recovery.
Most sports nutrition guidelines recommend high carbohydrate intake for athletes, but most research has focused on male athletes. This study matters because it specifically examined whether those same recommendations work the same way for female athletes, whose bodies have different hormonal patterns and energy needs. By carefully controlling food intake and measuring actual energy availability, the researchers could isolate carbohydrate’s specific effects.
This study was small (only 13 athletes), which limits how much we can generalize the findings. However, the researchers used rigorous methods: they provided all food to control intake precisely, used individually calibrated wearable devices to measure energy expenditure accurately, and tested multiple outcomes. The study was exploratory, meaning it was designed to generate questions for future research rather than provide definitive answers. Published in a peer-reviewed journal, the work represents solid preliminary evidence but shouldn’t be considered final proof.
What the Results Show
Both groups improved their strength significantly over the seven weeks. Bench pull strength increased by about 3.6 kilograms and bench press by 4.6 kilograms in both groups. Both groups also lost fat (about 1.1 kilograms) and gained muscle (about 1.2 kilograms). These improvements happened despite one group eating roughly double the carbohydrates of the other.
The high-carb group did have substantially more energy available to their bodies (45 calories per kilogram of fat-free mass daily versus 30 in the lower-carb group). This is important because energy availability is considered crucial for athletic performance and recovery. Yet this extra energy didn’t translate into better strength gains, faster running times, or higher jumps.
One surprising finding involved sleep: athletes in the lower-carb group actually slept longer on nights after training days. This contradicts the common assumption that more carbs improve recovery and sleep. Other sleep quality measures showed minimal differences between groups.
Blood markers showed minimal differences between groups. Iron levels (measured by ferritin) decreased in both groups by about 29 micrograms per liter, which is worth monitoring in female athletes since iron deficiency can affect performance. Thyroid function and cholesterol remained stable in both groups. Body composition changes were similar between groups, with both losing fat and gaining muscle at comparable rates.
Most sports nutrition research recommends 6-10 grams of carbs per kilogram of body weight for athletes doing intense training. This study challenges the assumption that higher carbohydrate intake automatically produces better results in female athletes. Previous research on male athletes often showed performance benefits from high-carb diets, but female athletes’ hormonal cycles and metabolic differences may mean they respond differently. This exploratory work suggests that individual variation matters more than previously thought.
The biggest limitation is sample size: only 13 athletes is very small, making it hard to spot real differences if they exist. The study lasted only seven weeks, so we don’t know if differences might appear over longer training periods. The athletes were semiprofessional, not elite, so results might differ for higher-level competitors. The study didn’t account for individual menstrual cycle phases, which can affect how female athletes use carbohydrates. Finally, the lower-carb group (3 grams per kilogram) still received moderate carbohydrate intake, not a truly low-carb diet, so we don’t know how very low carbohydrate intake would affect results.
The Bottom Line
Female athletes shouldn’t automatically assume they need maximum carbohydrate intake to improve performance. A moderate carbohydrate intake (3-6 grams per kilogram of body weight on training days) appears sufficient for strength and muscle gains during preseason training. Individual preferences, digestive comfort, and overall energy balance may matter more than hitting a specific carbohydrate target. Confidence level: Moderate (this is preliminary evidence from a small study).
Female rugby players and other female athletes doing intense strength training should pay attention to this research. Coaches and sports nutritionists working with female athletes should consider that standard male-based carbohydrate recommendations might not be optimal. This is less relevant for endurance athletes or very high-level competitors, who may have different carbohydrate needs. Athletes with iron deficiency concerns should note the iron level changes observed.
Strength and muscle changes appeared over the seven-week preseason period. Sleep differences emerged within the first few weeks. Most athletes would expect to notice performance changes within 4-6 weeks of adjusting carbohydrate intake, though individual variation is significant.
Frequently Asked Questions
Do female athletes need more carbohydrates than male athletes?
Research shows female athletes may not need the maximum carbohydrate intake traditionally recommended for male athletes. A 2026 study found female rugby players improved strength similarly on moderate carbs (3 g/kg) versus high carbs (6 g/kg), suggesting individual needs vary more than previously thought.
How much carbohydrate should female athletes eat on training days?
A 2026 exploratory study suggests 3-6 grams of carbohydrates per kilogram of body weight on training days may be sufficient for strength and muscle gains in female athletes, rather than the higher amounts often recommended. Individual tolerance and performance response matter more than hitting a specific target.
Does eating more carbs help female athletes sleep better after training?
Surprisingly, a 2026 study found female athletes eating lower carbohydrates (3 g/kg) actually slept longer on training nights than those eating double the carbs (6 g/kg), contradicting the common assumption that higher carbohydrate intake improves post-training sleep.
Can female athletes build muscle without eating maximum carbohydrates?
Research from 2026 shows female rugby athletes gained approximately 1.2 kilograms of muscle over seven weeks on moderate carbohydrate intake (3 g/kg daily), similar to those eating twice as much, indicating maximum carbs aren’t required for muscle development.
Should female athletes follow the same carbohydrate guidelines as male athletes?
A 2026 study suggests female athletes may respond differently to carbohydrate intake than males, with moderate amounts producing similar performance gains as high amounts. Coaches should consider individualizing recommendations rather than applying male-based guidelines universally.
Want to Apply This Research?
- Log daily carbohydrate intake (in grams per kilogram of body weight) alongside workout performance metrics (strength lifts, jump height, sprint times) to identify your personal carbohydrate sweet spot rather than following generic guidelines
- Experiment with moderate carbohydrate intake (3-6 grams per kilogram on training days) instead of maximizing carbs, and track how you feel, sleep, and perform to find what works best for your individual body
- Track sleep duration and quality, strength metrics, and energy levels weekly to identify patterns between carbohydrate intake and your personal recovery and performance, adjusting based on your individual response rather than following one-size-fits-all recommendations
This research is preliminary and based on a small group of 13 semiprofessional female rugby athletes over seven weeks. Individual nutritional needs vary significantly based on sport, training intensity, body composition, menstrual cycle phase, and personal metabolism. Athletes should not change their nutrition plans based solely on this study. Consult with a registered sports dietitian or qualified nutrition professional before making significant dietary changes, especially if you have existing health conditions, iron deficiency, or performance concerns. This article is for informational purposes and does not constitute medical or nutritional advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
