Effect of high dietary restraint on energy availability and menstrual status

Dietary restraint (DR) is a key eating behavior associated with menstrual disturbances (MD) in exercising women. However, the association between DR and energy availability (EA) has not been examined.

The objective of this study is 1) to compare EA in women when categorized by DR score, to include an evaluation of the frequency of women with low EA, and 2) to compare the distribution of subclinical and clinical MD between DR groups.

Exercising women (23 ± 4 yr; body mass index, 21.1 ± 1.9 kg·m; and exercise volume, 333 ± 198 min·wk) were retrospectively categorized by DR score into two groups: 1) women with high DR (n = 30) and 2) women with normal DR (n = 56). DR scores were obtained from the Three-Factor Eating Questionnaire. High DR score was defined as ≥13. Body composition was measured using dual-energy x-ray absorptiometry. EA was defined as energy intake - exercise energy expenditure per kilogram lean body mass (LBM). Low EA was defined as <30 kcal·kg LBM. Menstrual status was determined using daily urinary samples assayed for reproductive hormones.

EA was lower in the high DR versus the normal DR group (35.0 ± 12.9 vs 42.0 ± 12.9 kcal·kg LBM, P = 0.018). There was no difference (P = 0.866) in frequency of low EA between DR groups. There was a greater frequency of MD (amenorrhea, oligomenorrhea, anovulation, or luteal phase defect) in the high DR group (21/28, 75.0%) versus the normal DR group (24/47, 51.1%) (χ = 4.2, P = 0.041).

Our findings demonstrate that exercising women with high DR exhibited lower EA and a greater frequency of MD (subclinical and clinical) compared with women with normal DR. However, high DR was not associated with low EA in exercising women.