Intermittent Fasting for Menopause: Helpful Tool or Hormonal Stress?

What is intermittent fasting?

Fasting is a period of going without food or energy intake.

How long do people fast for?

People typically fast anywhere from 12 to 48 hours.

There are a variety of fasting lengths and patterns described in both popular media and scientific literature. The most studied fasting window is between 16 to 18 hours, which is what’s commonly referred to as intermittent fasting in research.

Here are a few examples of fasting patterns:

• Time-restricted feeding – eating during an 8-hour window, fasting for 16 hours (or other variations)• 24-hour fasts – done 1–2 times per week

• One Meal a Day (OMAD) – typically a dinner-to-dinner fast

• Alternate Day Fasting – eat normally one day, then fast or consume a small meal the next

• Fasting Mimicking Diet – developed by Dr. Valter Longo, this is a low-protein, low-calorie diet designed to mimic the physiological effects of fasting

Fasting is Biologically Familiar

Many traditional cultures and religions incorporate fasting — for example, during Ramadan. Fasting was a normal part of life for our hunter-gatherer and Paleolithic ancestors. When food was scarce, people had no idea when their next meal would come. Hunters could have success one day and nothing the next.

Our genes are familiar with fasting — more so than with constant food availability. This period in human history, where food is abundant and accessible 24/7, is unique. The average person now makes over 200 food-related decisions each day — whether it’s passing by a Starbucks, seeing a food ad, or deciding what to eat for lunch.

What are the benefits of intermittent fasting?

It turns out, the historical challenge of securing food had biological advantages. Different benefits of fasting show up at different stages:

• Once your body uses up its glucose stores, it can switch into ketosis — the goal of the popular ketogenic diet. At this point, the body begins using fatty acids for fuel, producing ketones as a byproduct. Ketones are especially good for brain health: they’re neuroprotective, can improve cognition, and reduce inflammation. Ketosis has also been studied in cancer.

• After about 12+ hours, growth hormone is stimulated. This supports bone density, cognitive function, mood, and body composition.

• After 16+ hours, autophagy is activated. Dr. Yoshinori Ohsumi won a Nobel Prize for his work on autophagy — a process where cells clean out damaged components, eliminate viruses and bacteria, and recycle waste. Think of it as cellular spring cleaning.

Research has linked fasting to improved blood sugar regulation, lower inflammation, enhanced brain function, and many other benefits. It’s being explored in conditions like Alzheimer’s, autoimmune diseases, and cancer.

Is it safe to fast?

Fasting isn’t recommended if you’re pregnant, nursing, growing, underweight, or have a history of eating disorders. While intermittent fasting is generally safe for most people, prolonged water or dry fasting should be done with medical supervision.

What’s the deal with fasting and perimenopause / postmenopause?

Have you seen the hot debate on social media about intermittent fasting? Fitness experts are going at it.

I was genuinely curious whether intermittent fasting benefits menopausal women — so I dug into the research and here’s what I found:

Most studies on intermittent fasting during perimenopause or postmenopause are conducted on sedentary women who are classified as overweight or “obese.” (I’m not a fan of the BMI — I cringe at using these terms — but what’s notable here is that the subjects were sedentary.)

Summary: Research shows positive effects of intermittent fasting on weight loss in sedentary, overweight pre- and postmenopausal women. Benefits include reduced inflammation, improved insulin resistance, fat loss, and lowered liver enzymes.

Want to geek out? Here are some highlights:

• Tavokoli et al (2025): In a randomized controlled trial, postmenopausal women with rheumatoid arthritis followed a 16-hour fasting window for 8 weeks. The results? Lower inflammation and reduced liver enzymes.

• Cienfuegos et al (2021): Over 8 weeks, women (pre and postmenopausal) who ate in a 4–6 hour window lost an average of 3.3 pounds. Both fat mass and lean mass were reduced. Blood sugar and insulin levels also improved.

• Jóźwiak et al (2024): When exercise was added to an 8-hour eating window, it helped preserve lean mass. The fasting + exercise group also had better results for blood sugar, insulin, waist size, and fat mass compared to fasting alone.

What about active women?

What about intermittent fasting for weight loss in active women?

Here’s where things get hairy. There’s one rodent study showing negative effects, and just one human study I know of involving menopausal women. Bottom line: we don’t really know yet — so I’m not sure what everyone’s fighting about online.

Let’s nerd out on that one human study…

• Kalam et al (2023): This was the first to look at intermittent fasting’s impact on hormones in older obese women. Participants followed a 4-hour eating window over 8 weeks. Both pre- and postmenopausal women lost 3–4% of their body weight. No major changes in hormones were reported — except a drop in DHEA levels. This could potentially affect skin, vaginal health, and long-term estrogen/testosterone levels. Methodology-wise, the study had flaws — including participants joining midway through.

Conclusion

Intermittent fasting is one simple change that can have a big impact. It doesn’t require new supplements, expensive foods, or overhauling what you eat — just when you eat. By narrowing your eating window, you could see improvements in cholesterol, insulin resistance, fat mass, weight, inflammation, and more.

It’s also flexible — you can gradually extend your fasting window from 10 to 14 hours, or from 12 to 16. Even 12-hour fasts (e.g., dinner to breakfast) have mild benefits. This is how our grandparents often ate: three meals a day, no snacks in between.

That said, intermittent fasting isn’t for everyone. It’s important to listen to your body.

• How’s your sleep?

• How’s your energy?

• How are your workouts?

Check in with your heart rate variability, too. If these start to decline, reassess.

And remember — cardio stimulates autophagy, much like fasting does. If you’re already training hard, fueling properly may be more important than fasting.

References

Cienfuegos S, Gabel K, Kalam F, Ezpeleta M, Lin S, Varady KA. Changes in body weight and metabolic risk during time restricted feeding in premenopausal versus postmenopausal women. Exp Gerontol. 2021 Oct 15;154:111545. doi: 10.1016/j.exger.2021.111545. Epub 2021 Aug 31. PMID: 34478825; PMCID: PMC8464526.

Jóźwiak B, Domin R, Krzywicka M, Laudańska-Krzemińska I. Effect of exercise alone and in combination with time-restricted eating on cardiometabolic health in menopausal women. J Transl Med. 2024 Oct 21;22(1):957. doi: 10.1186/s12967-024-05738-y. PMID: 39434160; PMCID: PMC11494798.

Kalam F, Akasheh RT, Cienfuegos S, Ankireddy A, Gabel K, Ezpeleta M, Lin S, Tamatam CM, Reddy SP, Spring B, Khan SA, Varady KA. Effect of time-restricted eating on sex hormone levels in premenopausal and postmenopausal females. Obesity (Silver Spring). 2023 Feb;31 Suppl 1(Suppl 1):57-62. doi: 10.1002/oby.23562. Epub 2022 Oct 6. PMID: 36203273; PMCID: PMC9877115.

Patterson RE, Laughlin GA, LaCroix AZ, Hartman SJ, Natarajan L, Senger CM, Martínez ME, Villaseñor A, Sears DD, Marinac CR, Gallo LC. Intermittent Fasting and Human Metabolic Health. J Acad Nutr Diet. 2015 Aug;115(8):1203-12. doi: 10.1016/j.jand.2015.02.018. Epub 2015 Apr 6. PMID: 25857868; PMCID: PMC4516560.

Tavakoli A, Akhgarjand C, Ansar H, Houjaghani H, Khormani A, Djafarian K, Rostamian A, Ranjbar M, Farsani GM. The effects of intermittent fasting on antioxidant and inflammatory markers and liver enzymes in postmenopausal, overweight and obese women with rheumatoid arthritis: a randomized controlled trial. Sci Rep. 2025 Jan 18;15(1):2357. doi: 10.1038/s41598-025-86734-0. PMID: 39825120; PMCID: PMC11742681.