Is Intermittent Fasting Good or Bad in Perimenopause?: What the Research Shows

Is Intermittent Fasting Good or Bad in Perimenopause?: What the Research Shows

A 2025 study tested time-restricted eating (eating only within an 8-hour window) combined with exercise in 59 perimenopausal and menopausal women. Over 12 weeks, adding fasting to exercise did not give any extra brain benefit over exercise alone. Fasting did not seem to cause any harm either — it simply added nothing on top of exercise for the brain tests measured.

Medical disclaimer: This article summarises published research for informational purposes only. It is not medical advice and is not a substitute for guidance from a qualified health professional. Always consult your doctor before starting any fasting protocol, especially if you have an existing health condition or take medication.

The Short Version

• What they tested: Eating only within an 8-hour window each day, combined with exercise, to see if it helped the brain during perimenopause and menopause.
• Who did it: Barbara Jóźwiak at Poznan University of Physical Education, published in Frontiers in Public Health in 2025.
• How many people: 59 people, all women. Ages are not stated in the abstract.
• How long: 12 weeks.
• What happened: Adding fasting to exercise gave no extra brain benefit compared to exercise alone.
• Read the study yourself: Frontiers in Public Health 2025 →

What They Wanted to Find Out

Many women notice foggy thinking during perimenopause. Researchers wanted to know if eating only within an 8-hour window, on top of exercise, could help with that. They were not just asking "does fasting help women" in general — they wanted to know if it adds anything beyond exercise alone.

This matters because women are often told fasting and exercise both help with menopause symptoms. If you want to see how fasting compares across different menopause studies, you can also read about time-restricted eating easing menopause symptoms more than exercise and fasting plus walking boosting muscle strength after menopause.

Who Was in the Study

Who they were: The women were in perimenopause, menopause, or past menopause. Their exact ages, weight, and health conditions are not stated in the abstract.

What the fasting actually looked like: The fasting group followed a 16:8 pattern. That means 16 hours without food and an 8-hour window to eat each day. Both groups did the same exercise program for 12 weeks.

What Happened

Adding a fasting window to exercise did not give extra brain benefits over exercise alone.

• Both groups got quicker on a brain working-speed test.
• Only the exercise-only group improved on a reading-focus test.
• Only the exercise-only group showed more activity on two brain-wave measures.
• Two blood markers tied to brain health did not change in either group.
• The researchers found no sign that fasting made thinking worse.

What Did Not Change

• A reading-focus test (called naming interference) stayed the same in both groups.
• Memory-test accuracy stayed the same in both groups.
• Two brain health blood markers stayed the same in both groups.
• Muscle was not measured in this study. It cannot tell us whether fasting changed muscle differently than exercise alone.

What the Researchers Said

The researchers concluded that adding fasting to exercise did not improve brain health more than exercise alone. They said exercise itself seems to be the main driver of brain benefits in menopausal women.

What This Means for You

• Exercise may matter more than fasting timing for brain health during perimenopause, based on this study.
• If you already exercise regularly, adding a fasting window may not boost your thinking further, according to these results.
• This study found no sign fasting harmed focus or memory in perimenopausal and menopausal women over 12 weeks.
• Women at every stage of the menopause transition were included, but results were not broken down by stage in the abstract.
• If you are curious about fasting and menopause more broadly, see how it affected cholesterol when combined with tai chi or fitness in postmenopausal women.
• This single study cannot say fasting is "good" or "bad" for perimenopause overall — it only tested brain tests, not hot flashes, mood, or sleep.

What This Study Could Not Tell Us

• Only 59 women took part, which is a small group.
• The study lasted 12 weeks. It cannot say what happens after a year.
• Every woman in the study also exercised, so it cannot say what fasting alone would do.
• The study measured brain tests, not everyday memory or mood.
• The funding source is not reported in the abstract.
• All participants were women, so there is no comparison to men in this study.

The Study Details

Jóźwiak, B., Kleka, P., & Laudańska-Krzemińska, I. (2025). Effect of exercise alone and in combination with time-restricted eating on cognitive health in menopausal women. Frontiers in Public Health. PMID: 40880914

Common Questions

Does intermittent fasting help with perimenopause symptoms?

This study only looked at brain tests, not hot flashes, mood, or sleep. It found exercise helped more than adding a fasting window on top of it.

Is intermittent fasting safe during perimenopause?

In this study, the women who fasted showed no signs of worse thinking or focus over 12 weeks. The study found no harm, but it was small and short.

Does fasting improve memory during menopause?

A memory test called the N-back test did not change in either group. Neither fasting plus exercise, nor exercise alone, improved memory scores.

Should I fast instead of exercising during perimenopause?

This study suggests exercise is the stronger factor for brain health. The exercise-only group improved on more tests than the group that also fasted.

How many women were in this fasting and perimenopause study?

59 women took part. 26 did fasting plus exercise, and 33 did exercise alone, over 12 weeks.

More Research Like This

• Time-Restricted Eating Eased Menopause Symptoms More Than Exercise
• Time-Restricted Eating Cuts Weight the Same in Both Menopause Stages
• Combining Fasting With Interval Workouts Helped Women Over 50 Get Fitter
• Time-Restricted Eating Works the Same Before and After Menopause
• Does Intermittent Fasting Help Menopause Night Sweats?
• Time-Restricted Eating Plus Tai Chi Improved Cholesterol in Menopause
• Fasting Plus Walking Boosted Muscle Strength in Postmenopausal Women

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