News | Weight Loss or Fertility Effects? The Mixed Impact of Intermittent Fasting on Female Hormones
Intermittent fasting (IF) is widely promoted for effective weight loss, but its effects on female reproductive hormones remain controversial. A research team at the University of Illinois Chicago (UIC) published a recent study in Obesity examining the effects of intermittent fasting on female hormones and providing new scientific evidence.
Led by UIC nutrition professor Krista Varady, the team followed a group of premenopausal and postmenopausal women with obesity who used the Warrior Diet intermittent fasting pattern for eight weeks. They ate only within a four- or six-hour window each day and fasted completely for the remaining hours, drinking only water.
Most reproductive hormone levels did not change significantly, but DHEA (dehydroepiandrosterone) levels fell by about 14%.
Study Finding: DHEA Levels Declined but Remained Within the Normal Range
DHEA is a steroid hormone widely used in fertility treatment to support ovarian function and egg quality. The study found an approximately 14% decline in DHEA levels in both premenopausal and postmenopausal women.
Although the change was notable, the researchers said levels remained within the normal range. This means:
For premenopausal women, the effect of lower DHEA may be minimal, and weight loss itself may improve fertility, so the benefits and risks need to be considered together.
For postmenopausal women, a further reduction in DHEA may warrant attention because menopause itself lowers estrogen. However, the study found no adverse effects such as reduced sexual function or skin changes from the lower DHEA.
The study also found:
✅ Sex hormone-binding globulin (SHBG) — Levels of this protein, which carries reproductive hormones, did not change.
✅ Testosterone and androstenedione — Levels of both hormones remained stable.
✅ Progesterone, estradiol, and estrone — These hormones were measured only in postmenopausal women and did not change after the eight-week study.
Health Benefits of Intermittent Fasting: Weight Loss and Reduced Insulin Resistance
The study also indicated that intermittent fasting had limited hormonal effects while providing health benefits.
Weight loss — Women in the study lost an average of 3% to 4% of their body weight over eight weeks, while the unrestricted control group had almost no weight change.
Improved insulin sensitivity — Participants had a marked reduction in insulin resistance, which may indicate a lower risk of diabetes.
Improved antioxidant capacity — Intermittent fasting reduced biomarkers of oxidative stress, which may support healthy aging and overall health.
A moderate reduction in DHEA may also offer an additional health benefit. High DHEA levels are associated with breast cancer risk, and the researchers suggested that a moderate reduction might help lower this risk in women.
Future Outlook: Is Intermittent Fasting Suitable for Women?
Although the study provides important data, several questions remain:
Does lower DHEA affect long-term fertility? — The study lasted only eight weeks and could not determine the long-term effects of reduced DHEA on female reproductive health.
Is intermittent fasting suitable for all women? — The study excluded perimenopausal women around age 40, so hormonal changes in this group remain unclear.
Should the fasting window be adjusted? — The study used four- and six-hour eating windows. Future research may need to examine longer windows, such as eight hours.
Professor Krista Varady said:
“We have observed thousands of premenopausal and postmenopausal women lose weight through different intermittent fasting patterns, such as alternate-day fasting and time-restricted eating. The core principle is simple: shorten the eating window and reduce calorie intake.
Most negative information about intermittent fasting currently comes from animal studies. We need more human research to understand its long-term effects.”
Conclusion: Intermittent Fasting May Be Worth Considering, but Requires Individual Assessment
This study provides important evidence that intermittent fasting has limited effects on female reproductive hormones while offering benefits such as weight loss and improved insulin sensitivity, with a possible reduction in breast cancer risk.
✅ For women seeking weight loss, intermittent fasting can be effective and appears to have little effect on reproductive hormones.
⚠ For menopausal women, lower DHEA may compound the decline in estrogen, so medical guidance is recommended.
Women planning pregnancy should weigh the benefits and risks with a medical professional and choose the most suitable eating pattern.
Longer and larger human studies remain a priority to determine the full effects of intermittent fasting on women's health.
News | Weight Loss or Fertility Effects? The Mixed Impact of Intermittent Fasting on Female Hormones
News | Weight Loss or Fertility Effects? The Mixed Impact of Intermittent Fasting on Female Hormones
Intermittent fasting (IF) is widely promoted for effective weight loss, but its effects on female reproductive hormones remain controversial. A research team at the University of Illinois Chicago (UIC) published a recent study in Obesity examining the effects of intermittent fasting on female hormones and providing new scientific evidence.
Led by UIC nutrition professor Krista Varady, the team followed a group of premenopausal and postmenopausal women with obesity who used the Warrior Diet intermittent fasting pattern for eight weeks. They ate only within a four- or six-hour window each day and fasted completely for the remaining hours, drinking only water.
Most reproductive hormone levels did not change significantly, but DHEA (dehydroepiandrosterone) levels fell by about 14%.
Study Finding: DHEA Levels Declined but Remained Within the Normal Range
DHEA is a steroid hormone widely used in fertility treatment to support ovarian function and egg quality. The study found an approximately 14% decline in DHEA levels in both premenopausal and postmenopausal women.
Although the change was notable, the researchers said levels remained within the normal range. This means:
For premenopausal women, the effect of lower DHEA may be minimal, and weight loss itself may improve fertility, so the benefits and risks need to be considered together.
For postmenopausal women, a further reduction in DHEA may warrant attention because menopause itself lowers estrogen. However, the study found no adverse effects such as reduced sexual function or skin changes from the lower DHEA.
The study also found:
✅ Sex hormone-binding globulin (SHBG) — Levels of this protein, which carries reproductive hormones, did not change.
✅ Testosterone and androstenedione — Levels of both hormones remained stable.
✅ Progesterone, estradiol, and estrone — These hormones were measured only in postmenopausal women and did not change after the eight-week study.
Health Benefits of Intermittent Fasting: Weight Loss and Reduced Insulin Resistance
The study also indicated that intermittent fasting had limited hormonal effects while providing health benefits.
Weight loss — Women in the study lost an average of 3% to 4% of their body weight over eight weeks, while the unrestricted control group had almost no weight change.
Improved insulin sensitivity — Participants had a marked reduction in insulin resistance, which may indicate a lower risk of diabetes.
Improved antioxidant capacity — Intermittent fasting reduced biomarkers of oxidative stress, which may support healthy aging and overall health.
A moderate reduction in DHEA may also offer an additional health benefit. High DHEA levels are associated with breast cancer risk, and the researchers suggested that a moderate reduction might help lower this risk in women.
Future Outlook: Is Intermittent Fasting Suitable for Women?
Although the study provides important data, several questions remain:
Does lower DHEA affect long-term fertility? — The study lasted only eight weeks and could not determine the long-term effects of reduced DHEA on female reproductive health.
Is intermittent fasting suitable for all women? — The study excluded perimenopausal women around age 40, so hormonal changes in this group remain unclear.
Should the fasting window be adjusted? — The study used four- and six-hour eating windows. Future research may need to examine longer windows, such as eight hours.
Professor Krista Varady said:
“We have observed thousands of premenopausal and postmenopausal women lose weight through different intermittent fasting patterns, such as alternate-day fasting and time-restricted eating. The core principle is simple: shorten the eating window and reduce calorie intake.
Most negative information about intermittent fasting currently comes from animal studies. We need more human research to understand its long-term effects.”
Conclusion: Intermittent Fasting May Be Worth Considering, but Requires Individual Assessment
This study provides important evidence that intermittent fasting has limited effects on female reproductive hormones while offering benefits such as weight loss and improved insulin sensitivity, with a possible reduction in breast cancer risk.
✅ For women seeking weight loss, intermittent fasting can be effective and appears to have little effect on reproductive hormones.
⚠ For menopausal women, lower DHEA may compound the decline in estrogen, so medical guidance is recommended.
Women planning pregnancy should weigh the benefits and risks with a medical professional and choose the most suitable eating pattern.
Longer and larger human studies remain a priority to determine the full effects of intermittent fasting on women's health.
Story source:
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