REF-1206 · James et al., 2001 · European Journal of Applied Physiology · Paper · PubMed

Can women carb-load as well as men?

Yes, if they eat as much: on 12 g/kg lean mass a day for 3 days, trained women's muscle glycogen rose about as much as men's, in both cycle phases. About 12 athletes; abstract only.

Blimited evidenceMeasured on trained to highly trained athletes

Tarnopolsky's 1995 study had reported that women could not accumulate supranormal muscle glycogen on a loading diet, but its women ate much less carbohydrate per kilogram than its men.

James et al. re-tested the question with intakes matched to lean mass: endurance-trained women and men ate 12 g of carbohydrate per kg of lean body mass a day for 3 days while stopping their daily training. Glycogen rose from 108 to 193 mmol/kg wet weight in the women in the post-menstrual phase, from 111 to 202 in the pre-menstrual phase, and from 109 to 183 in the men.

The authors conclude that female athletes can supercompensate and that, fed comparable carbohydrate relative to lean mass, men and women do not differ.

Our reading: together with REF-1205 this answers "can women carb-load?" with yes, if they eat enough; the abstract gives no statistics and the groups were about six each, so "no difference" is no evidence of a difference, and the descriptive synthesis in REF-1204 reaches the same reading across studies (sex was not pooled or tested there, and this study is one of those it cites).

Protocol

Design (from the abstract): endurance-trained women and men; glycogen measured before and after 3 days of 12 g carbohydrate per kg lean body mass per day "in conjunction with the cessation of their daily physical training"; the women were studied in the post-menstrual and in the pre-menstrual phase.
Who: n not given in the abstract; the Jones 2026 review tabulates 6 men and 6 women (REF-1204, full-text Table 1).
Not given in the abstract: how lean mass was measured, the absolute intakes, the food used, any depleting exercise before loading, the biopsy site, the order of the two menstrual-phase trials, contraceptive use, the statistical tests, and funding.

Key Results

GroupBefore (mmol/kg wet weight, mean (SD))After 3 daysRise (our arithmetic)
Women, post-menstrual phase108 (15)193 (14)+85 (+79%)
Women, pre-menstrual phase111 (16)202 (20)+91 (+82%)
Men109 (27)183 (25)+74 (+68%)
Conclusions as stated in the abstract: women can accumulate supranormal muscle glycogen; with comparable carbohydrate relative to lean mass there is no sex-related difference in that ability. The abstract reports no P values or confidence intervals.
Secondary source, not this abstract: the Jones 2026 review (REF-1204, full-text Table 1) gives the intake per kg of body mass as 10.5 g/kg/day (872 g) for the men and 9.9 g/kg/day (684 g) for the women, and the loaded glycogen in dry mass as 796.1 (men), 878.7 (pre-menses) and 839.6 mmol/kg (post-menses). Matching to lean mass therefore gave the women slightly less per kg of body weight than the men.

Mechanisms

Measured: a near doubling of muscle glycogen in both sexes and both menstrual phases on the same lean-mass-relative intake.
Authors' interpretation: the earlier report of a sex difference came from feeding women much less carbohydrate relative to body mass than men; capacity to store is not lower in women.
Inference: because women carry more fat mass, a dose set per kg of body mass gives them more per kg of muscle, and one set per kg of lean mass gives them less per kg of body mass; at around 10 g/kg body mass either way the stores rose as much as the men's in this study.

Practical Application

Can women carb-load as well as men? Yes, if they eat as much: on 12 g/kg lean mass a day for 3 days, trained women's muscle glycogen rose about as much as men's, in both cycle phases. About 12 athletes; abstract only.
The usual body-mass dose is enough: in this study 12 g/kg lean mass came to about 10 g/kg body mass (9.9 in the women, 10.5 in the men; review's tabulation, REF-1204), at the low end of the 10-12 g/kg/day of REF-748, though given for 3 days rather than 1-2; no separate women's rule is needed.
Cycle phase: stores rose similarly in the pre- and post-menstrual phases at this intake; REF-1204 notes no phase difference at 8-10 g/kg/day, but on two studies, one of them this one (the other McLay 2007), so it is not independent support. Race day and cycle phase rarely line up by choice anyway; symptoms are coached by SYNTH-37.
When women "don't load": the usual reason is too little food overall (REF-1205); check total energy and low energy availability first (SYNTH-54).
Rest versus a taper: these athletes stopped training for the 3 days; light sessions of up to about an hour did not appear to lower glycogen at very high intakes in a between-study comparison (REF-1204; not a pooled estimate), so a normal taper does not need full rest to load.
Only for long events: loading pays past about 90 min (REF-819, B+).

Limitations

Abstract only. The full text (Springer) was not available open access; group sizes, statistics, lean-mass method and the order of the menstrual-phase trials are not in the abstract.
Small and descriptive in the abstract: about six per sex (by the review's count) and no test values, so the conclusion of no sex difference means no evidence of a difference in a small study.
Full rest during loading, a diet indexed to lean mass and fixed for 3 days: not the way most athletes taper or count food.
Glycogen only, wet weight in the abstract; no performance outcome.
Funding and conflicts: not given in the abstract.
How this entry was checked and changed
Why this level

from the abstract; small (n = 12 as tabulated by the Jones 2026 review REF-1204, 6 women and 6 men; the abstract gives no n), before-after design with a between-sex comparison, glycogen outcome only