Exercise Induced Period Dysfunction Improved with Extra Calories

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Exercise induced period dysfunction improved with extra calories

Randomised controlled trial of the effects of increased energy intake on menstrual recovery in exercising women with menstrual disturbances: the ‘REFUEL’ study



The female athlete triad describes the relationship between energy deficiency, menstrual dysfunction and low bone density.

The recommended treatment in these cases of irregular cycles and low bone density is to increase energy intake.

However published reports on the efficacy of increased food intake in reversing irregular cycles (oligomenorrhoea and amenorrhoea) is of limited quality.

The amount of additional energy required, over what timeframe and the associated metabolic changes remains unanswered.


To establish whether a 12-month intervention of increased energy intake leads to menstrual recovery in women with severe exercise-associated menstrual dysfunction.


Women aged 18-35 years (BMI 16-25 kg/m2) with no reported menses in the 3 months prior, or in 6 of the past 12 cycles, were recruited for initial assessment.

Any woman diagnosed with primary amenorrhoea, chronic illness, eating or psychiatric disorder, in poor health, exercising less than 2 hours a week, dieting or smoking, under hormonal therapy (past 6 months) or other medication which alters metabolic or reproductive hormones, were excluded from the study to minimise potential bias.

Eligible women were then randomised into 2 groups. Group 1 (Extra Calories) had increased energy intake, for a total of 12 months, while the control group (Group 2) was asked to maintain both exercise and energy intake levels for the same duration.

Both groups were supplemented with calcium (1200mg) and vitamin D3 (400IU) daily to ensure adequate levels.

In the extra calories group, an additional 20-40% increase in energy intake above baseline energy requirements was prescribed with counselling provided by a clinical dietician.

Energetic and reproductive status was regularly assessed during all stages of the study: screening, 4-week baseline, 12-month intervention and post-study.

Body weight was measured twice a week while energy intake was recorded monthly using 3-day diet logs. Daily exercise energy expenditure was estimated monthly by averaging a 7-day monitoring period while dual-energy X-ray absorptiometry (DXA) was utilised for analysis of body composition.

Finally, blood samples were collected once a month, for the first 6 months, and then every 3 months afterwards to record metabolic hormone levels.


Following initial screening and baseline monitoring 76 women with menstrual dysfunction (oligomenorrhoea or amenorrhoea) was randomised into the 2 groups, 40 in the Extra Calories group and 36 in the Control group.

Of these 76 women, only 33 completed the entire 12-month study (17 extra calories, 16 control).
Initial screening of endocrine parameters confirmed functional hypothalamic amenorrhoea (FHA) in both groups of women. There was no significant difference in the proportion of oligomenorrhoeic and amenorrhoeic women across the 2 groups.

Following on from the 12-month trial, intention-to-treat (all 76 women) statistical analysis of the results, after adjustment for baseline fat mass and menstrual status, found that the likelihood of experiencing a menses in the Extra Calories group was almost twice as likely (91% increase) compared to the control group.

Further statistical analysis showed that women with a higher baseline (initial) fat mass were 8% more likely to experience menses per each additional kilo of fat while baseline menstrual status (oligomenorrhoea, amenorrhoea or ambiguous) showed no correlation.

Next analysis of reproductive outcomes in women with a clear baseline menstrual status (oligomenorrhoea or amenorrhoea) across the groups (Extra Calories, n=28; Control, n=26) showed that overall 64% of women in the Extra Calories group had improved menstrual function compared to just 19% in the control group.

More specifically according to baseline menstrual status;

  • 65% of amenorrhoeic women and 63% of oligomenorrhoeic women improved menstrual function (Extra Calories group)
  • 18% of amenorrhoeic women and 20% of oligomenorrhoeic women improved menstrual function (Control group)

Time wise, 12/18 (67%) women in the Extra Calories group recovered menstrual function within the first 3 months of intervention, followed by another 2 women or 14/18 (78%) recovered within 6 months of intervention, with the final 4 women recovering in the last 6 months of intervention.

Secondary analysis of energy intake levels showed a mean increase of 434kcal/day (23%) across the 17 women (Extra Calories group) who completed the study causing a 0.9kg and 2.6kg increase in body weight, at 3 and 12 months respectively.

DXA analysis showed that the majority of this increase was in fact fat mass (2.0kg) resulting in a 2.7% increase in body fat percentage.

Finally, the metabolic hormone, total triiodothyronine was increased significantly (+9ng/dl) by the end of the intervention as a direct result of improved metabolism.


In this study, women who exercised on average 303 ±33 mins/week and lost their period regularly were able to successfully restore their period in 64.3% of cases simply by increasing their energy intake levels (+434 calories/day) over 12 months, with no change to exercise levels.


  1. High drop out rate resulting in small final group sizes
  2. Change in reproductive hormone levels not measured


This research was supported by grants from the U.S. Department of Defense, U.S. Army Medical Research and Material Command, and the National Center for Advancing Translation Sciences, National Institutes of Health.


Self-reporting of no menses for at least 3 months prior to the study and no evidence of menses during baseline measurement.

Self-reporting of <3 menses in the past 3 months, or < 7 menses in the past 12 months or a a menstrual cycle length of 36–89 days during baseline measurement.

A group of three signs or symptoms which characterise a specific medical condition.

Similar studies

Cialdella-Kam L, et al. (2014). Dietary intervention restored menses in female athletes with exercise-associated menstrual dysfunction with limited impact on bone and muscle health. https://doi.org/10.3390/nu6083018

De Souza M J, et al. (2014). 2014 Female Athlete Triad Coalition Consensus Statement on Treatment and Return to Play of the Female Athlete Triad: 1st International Conference held in San Francisco, California, May 2012 and 2nd International Conference held in Indianapolis, Indiana, May 2013. https://doi.org/10.1136/bjsports-2013-093218

Guebels C P, et al. (2014). Active women before/after an intervention designed to restore menstrual function: resting metabolic rate and comparison of four methods to quantify energy expenditure and energy availability. https://doi.org/10.1123/ijsnem.2012-0165

Łagowska K, et al. (2014). Effects of dietary intervention in young female athletes with menstrual disorders. https://dx.doi.org/10.1186/1550-2783-11-21

Łagowska K, et al. (2014). Nine–month nutritional intervention improves restoration of menses in young female athletes and ballet dancers. https://doi.org/10.1186/s12970-014-0052-9


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