Energy Deficiency Due to Short-term Fasting, Hormonal Contraception
Conditions
Brief summary
The purpose of the present study is to characterize the endocrine and metabolic responses to a modest, short-term energy deficiency (\ 250 kcal/day) across the menstrual cycle in recreationally active women using different contraceptive methods (oral contraceptive, hormonal IUD, and non-hormonal IUD). This study will leverage daily urinary hormone metabolite tracking and comprehensive metabolic assessments, providing foundational data addressing an important and previously unexamined interaction between energy availability and hormonal regulation in contraceptive users.
Detailed description
The purpose of the present study is to characterize the endocrine and metabolic responses to a modest, short-term energy deficiency (\ 250 kcal/day) across the menstrual cycle in recreationally active women using different contraceptive methods. The investigators will be focusing on oral contraceptive users, hormonal IUD, and non-hormonal (i.e., copper IUD). Daily urinary hormone metabolite tracking and comprehensive metabolic assessments (i.e., resting metabolic rate, body composition via DXA, exercise logs, and energy intake) will be used to provide foundational data addressing an important and previously unexamined interaction between energy availability and hormonal regulation in contraceptive users. Based on evidence that female reproductive hormones are sensitive to energetic stress, that estrogen plays a central role in regulating metabolism and endocrine function, and that hormonal contraceptive methods differentially alter endogenous hormone profiles, the central hypothesis of this study is that a modest, controlled energy deficiency (\ 250 kcal/day) will alter reproductive hormone profiles across the menstrual cycle in recreationally active women using contraceptives. Specifically, it is hypothesized that changes in urinary reproductive hormone measures will be detectable during an energy-deficient cycle compared to a baseline cycle, and that the magnitude and pattern of these changes will differ by contraceptive type, with hormonal oral contraceptive users demonstrating a different hormonal response to energy deficiency than copper or hormonal intrauterine device users. A secondary hypothesis is that energy deficiency-induced hormonal changes will be associated with alterations in resting metabolic rate and body composition, and that these associations may be moderated by exercise energy expenditure and perceived stress. Collectively, these hypotheses are grounded in prior research demonstrating hormonal sensitivity to energetic perturbations and the distinct endocrine environments created by different contraceptive methods, while addressing a clear gap in the current literature regarding the interaction between energy availability and hormonal regulation in contraceptive users.
Interventions
BEHAVIORALEnergy Deficiency of approximately ~250 kcal/day
Following an initial baseline menstrual cycle, participants will be subjected to at least two weeks of a \~250 kcal/day energy deficit monitored through daily diet tracking.
Sponsors
University of Southern California
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
SCREENING
Masking
NONE
Intervention model description
There will be three groups: oral contraceptive users, hormonal IUD users, and non-hormonal IUD users that will all undergo the same protocol. The first cycle will involve a baseline assessment of urinary hormone metabolites. The second cycle will involve an imposed energy deficiency for at least 2 weeks will continuous hormone monitoring.
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 35 Years
Healthy volunteers
No
Inclusion criteria
* Female, aged 18-35 years * Recreationally active (engaging in structured exercise between 8-15 hours per week) * BMI of 18.5-29.9 as a BMI below or above these cut points results in highly varied menstrual cycle lengths17 * Not currently experiencing an eating disorder or disordered eating, or having a diagnosed eating disorder in the last 3 years * Non-pregnant or planning to become pregnant * Medically free from chronic diseases * Currently using one of the following contraceptive methods for ≥3 months: Monophasic oral contraceptive * Hormonal intrauterine device (H-IUD) * Copper intrauterine device * Weight stable (no weight change \>5% body weight within the past 3 months) * Weight greater than or equal to 110 lbs * Not suffering from known gynecological disease (i.e., PCOS, endometriosis, etc.) that may influence menstrual cycle regularity * Willing and able to maintain current exercise habits throughout the study * Willing to follow study dietary guidance to achieve a \~250 kcal/day energy deficit during Cycle 2
Exclusion criteria
* Amenorrhea or oligomenorrhea * Perimenopausal or menopausal * Currently pregnant, planning pregnancy, or breastfeeding * Use of hormonal contraception other than monophasic oral contraceptives or hormonal IUD (implant, nuvaring, etc.) * Initiation or change of contraceptive method within the past 3 months * Diagnosis of polycystic ovary syndrome (PCOS), endometriosis, hypothalamic amenorrhea, or other known reproductive endocrine disorder * Current or history of eating disorder or clinically diagnosed disordered eating * Current participation in intentional weight loss or weight gain program * Use of medications known to affect metabolism or hormone levels (e.g., systemic corticosteroids, thyroid medications, insulin, GLP-1 agonists) * Known metabolic, cardiovascular, renal, hepatic, or endocrine disease * Musculoskeletal injury limiting exercise participation within the past 3 months * Smoking or nicotine use * Contraindications to DXA scanning (e.g., pregnancy, recent high-radiation diagnostic imaging exceeding institutional limits) * Inability or unwillingness to comply with study procedures
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Urinary hormone exposure | From enrollment to energy deficit menstrual cycle is 3 months/90 days | Participants will be asked to track daily urine concentrations of estrogen and progesterone throughout a baseline (i.e., non-energy-deficient state) menstrual cycle and a menstrual cycle with an imposed energy deficit. The outcome will compare hormone exposure measured by the urinary concentrations between the two cycles. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Estimated versus actual resting metabolic rate | From enrollment to completion 90 days/3 months | Body composition and estimated metabolic rate will be collected using DXA. The DXA will be measured at baseline and at the conclusion of the energy-deficient menstrual cycle. Resting metabolic rate will be measured via indirect calorimetry testing at baseline, at the beginning of the second monitored (i.e., energy-deficient) menstrual cycle, and at the conclusion of the energy-deficient menstrual cycle. The estimated and actual metabolic rate will be compared as an assessment of energy status. Participants will also be asked to track exercise using a paper log or wearable device to estimate exercise energy expenditure (EEE), and daily intake (EI) will be measured via a paper log or an application. These values will be subtracted (EI-EEE) and normalized to fat-free mass collected via DXA to estimate energy availability. |
| Eating behaviors and attitudes will be measured using the EDEQ and the Three Factor Eating Questionnaire | From enrollment to conclusion 90 days/3 months | The Eating Disorder Examination Questionnaire is a 12 item questionnaire scaled from 0 to 3 (0 being 0 days and 3 being 6 to 7 days) assessing feelings around eating behaviors, body image, and restraint. The Three Factor Eating questionnaire is an 18-question survey that assesses cognitive restraint, emotional eating, and uncontrolled eating on a 4 point Likert scale (0 being never and 3 being at least once a week). |
| Subjective stress levels will measured using the Perceived Stress Scale | From enrollment to conclusion 90 days/3 months | The Subjective Stress Scale measures percieved stress through 10 questions about recent stress perceptions on a 0 to 4 Likert scale (0 being never; and 4 being very often). |
| Low Energy Availability Indicators will be assessed using the LEAF-Q | From enrollment to conclusion 90 days/3 months | The low energy availability in Females Questionnaire (LEAF-Q) is used to identify female athletes 'at risk' of low energy availability. This questionnaire assesses physiological symptoms associated with LEA, including 25 questions arranged into 3 sections; eating and reproductive assessment, injury assessment, and gastrointestinal symptom assessment. A total score of ≥8 out of 25 questions indicates that the athlete is at risk of LEA. There is a standardized scoring system that varies by question and subquestion. |
| Body composition will be measured using DXA | From enrollment to conclusion 90 days/3 months | Dual-energy x-ray absorbtometry will be used to assess body composition including segmental analysis of body fat and lean mass. |
Countries
United States
Contacts
CONTACTEmily Lundstrom, PhD
Outcome results
None listed