Intermittent Fasting and Fertility: What You Need To Know

Another day, another headline about something that may (or may not) affect fertility. If you’re in the throes of trying to conceive, we understand how this goes: You read and analyze and hold on to every piece of information that comes your way. You do your very, very best to reconfigure your lifestyle so that everything you eat or drink or do best aligns with recommendations from the ever-evolving body of research surrounding reproductive health. Maybe you even do this at the expense of your mental and physical health, because there’s a lot of information out there, but not a lot of clarity surrounding so much of that information.

Intermittent fasting has gone from wellness buzzword to fertility question almost overnight. If you’re trying to conceive and wondering whether skipping meals, time-restricted eating, or fasting windows could help or hurt your chances, you’re not alone. The short answer is that there isn’t a universal effect. How intermittent fasting impacts fertility seems to depend on body weight, overall health, hormone balance, and the type of fasting being used.

Most research on intermittent fasting focuses on metabolic health, not fertility directly. Some of the pathways overlap, especially around insulin sensitivity and hormone signaling, but the outcomes aren’t consistent across bodies. A 2025 study for Food Science & Nutrition found that intermittent fasting can improve metabolic markers for some people, while noting wide variability based on sex, baseline weight, and hormonal context. But when energy intake drops too low, though, reproductive hormones can be affected.

That’s why fertility and fasting can’t be boiled down to a simple yes or no. Context matters, and so does mental health, which often gets left out of the conversation.

What is intermittent fasting?

Intermittent fasting is a broad umbrella term for eating patterns that move between eating and fasting windows. It’s not about cutting out certain foods or following rigid meal rules. It’s about when you eat, which is why it can sound simple on paper but feel very different in real life, depending on the approach.

One of the most common styles is time-restricted feeding, often shortened to TRF. This means eating within a set daily window, like 8 to 10 hours, and then fasting outside of that window.

Another method is alternate-day fasting, or ADF. With this approach, eating patterns flip-flop between days of regular intake and days where calories are very limited or skipped altogether.

The 5:2 diet works a little differently. You eat normally most of the week, then significantly cut calories on two nonconsecutive days.

They’re all considered intermittent fasting, but they don’t ask the same things of your body. And when hormones and fertility are part of the equation, those differences matter far more than the label itself.

Does intermittent fasting affect fertility?

Short answer? It depends. Intermittent fasting doesn’t land the same way for everyone, and fertility is one of those areas where context really matters. How your body responds can depend on things like body weight, metabolic health, hormone balance, stress levels, and how intense or restrictive the fasting pattern is. That’s a lot of moving pieces, which is why this topic doesn’t lend itself to simple yes or no answers.

Fertility is closely tied to energy availability. When your body senses that fuel is inconsistent or insufficient, it can start conserving energy by dialing back processes that aren’t essential for survival, including reproduction. A 2008 study published in Ageing Research Reviews explains that low energy intake can suppress signaling along the hypothalamic pituitary ovarian axis, the system that helps regulate ovulation and menstrual cycles. This response tends to be stronger in people who are already lean, very active, or under ongoing stress.

At the same time, metabolic health plays a role too. For people with insulin resistance or PCOS, improving insulin sensitivity can help support more regular ovulation. According to a 2014 review in Physiology & Behavior, approaches that improve insulin signaling may positively influence reproductive hormone balance in some individuals. Intermittent fasting can support those pathways for certain people, but it’s not the only option, and it isn’t without tradeoffs.

What most headlines leave out is the full picture. The type of fasting, how long it’s been practiced, total calorie intake, sleep, mental health, and where you are in your reproductive journey all matter. That’s why intermittent fasting can feel helpful or neutral for one person, while subtly disrupting cycles or ovulation for another. Fertility isn’t delicate, but it is responsive, and timing-based eating patterns interact with it in very personal ways.

Fasting and fertility in women: What the research says

The latest research points to one big takeaway: context is everything. A 2024 review for Current Nutrition Reports looked at intermittent fasting and female reproductive health and found that fertility outcomes depend heavily on baseline metabolic health, body weight, and how intense the fasting approach is. In other words, intermittent fasting isn’t automatically good or bad for fertility. Its impact shifts based on who’s doing it and how. More restrictive approaches may disrupt reproductive hormones, while gentler patterns may support balance in certain groups.

This matters because women’s reproductive systems are especially sensitive to energy availability. Fertility tends to respond quickly to changes in intake, stress, and routine, which is why the same fasting plan can feel supportive for one person and destabilizing for another.

For women with PCOS or obesity

For women with PCOS or higher body weight, intermittent fasting may offer fertility-related benefits by improving metabolic and hormonal markers. A 2021 study published in the Journal of Translational Medicine found that fasting-based approaches, including the 5:2 diet and time-restricted feeding, were linked to lower androgen levels, higher sex hormone binding globulin (SHBG), and more regular menstrual cycles in women with PCOS. These shifts matter because elevated androgens and low SHBG are closely tied to ovulatory challenges.

Still, the research is clear that structure and adequacy are key. These approaches appear most helpful when they’re well nourished, thoughtfully planned, and supported by medical guidance. Pushing restrictions too far can work against hormonal balance, even in people who may benefit metabolically.

For healthy-weight women

For women who are already at a healthy weight with regular cycles, the story changes. Some evidence suggests that more aggressive fasting patterns may place unnecessary stress on the reproductive system. A 2022 review in Advances in Nutrition found that alternate-day fasting and strict 8-hour eating windows were associated with changes in luteinizing hormone patterns and increased cycle variability in some normal-weight women, particularly when calorie intake dropped without intention.

For this group, the goal isn’t to push through discomfort because a method is popular. Signals like cycle changes, rising fatigue, sleep disruption, or increased food focus are worth paying attention to. Fertility tends to do best with consistency, enough fuel, and a sense of safety in the body, even if that doesn’t make for a catchy headline.

Intermittent fasting for PCOS and fertility

For people with PCOS, intermittent fasting often comes up because of how closely PCOS is tied to insulin and androgen levels. Insulin resistance is common with PCOS, and when insulin runs high, androgens tend to follow. That hormonal combo can make ovulation less predictable, which is why eating patterns that support metabolic health get so much attention in PCOS fertility conversations.

Still, intermittent fasting isn’t a cure-all, and it doesn’t work the same way for everyone with PCOS. The research consistently shows that any potential benefits are more likely when fasting is paired with enough overall nutrition, regular meals, and other supportive strategies like strength training, stress reduction, and medical care when needed. A 2024 review in the Journal of Clinical Medicine cautions that overly restrictive eating can actually worsen hormonal disruption, even in people with insulin resistance.

When it’s used thoughtfully and with guidance from a clinician, intermittent fasting may fit into a broader PCOS fertility plan. It’s a tool, not a silver bullet, and it works best alongside approaches that support your hormones rather than push them harder.

Can intermittent fasting help with fertility?

For some people, yes. For others, not so much. Intermittent fasting may support fertility when it helps improve underlying metabolic factors that influence ovulation, like insulin resistance, higher androgen levels, or irregular cycles. In those situations, fasting isn’t directly “boosting” fertility. It’s helping the body get into a steadier place where the reproductive system can do its job more consistently.

Where intermittent fasting tends to fall short is when it turns into under-fueling or added stress. When the body doesn’t get enough energy, reproductive hormone signaling can slow down, even in people who otherwise feel healthy. That’s why some women notice later ovulation, missed periods, or cycle changes after jumping into more restrictive fasting patterns.

You’ll also see plenty of personal stories that say something like “intermittent fasting helped me get pregnant.” Those experiences are real, and they matter, but they’re also anecdotal. Often, several things are changing at once, such as weight stabilization, better blood sugar control, or reduced inflammation. Intermittent fasting may be part of that mix, but it’s rarely the whole story on its own.

Can I do intermittent fasting while pregnant?

It’s not recommended. Pregnancy increases your body’s need for consistent energy and nutrients, and intentionally extending fasting windows can make it harder to meet those needs. Major medical organizations, including the American College of Obstetricians and Gynecologists, emphasize the importance of regular meals and adequate calorie intake during pregnancy to support fetal growth and maternal health.

Most of what we know about fasting during pregnancy comes from observational research on Ramadan fasting. A small 2018 study for the Journal of Nutritional Science found that fasting during Ramadan may be associated with higher rates of maternal fatigue and dehydration, and some studies linked it to lower birth weight, especially when fasting occurred in the first trimester, but there was still not enough evidence overall.

If you were practicing intermittent fasting before pregnancy, it’s worth having a conversation with your OB-GYN or midwife early on. They can help you adjust your eating pattern to support both you and your baby safely.

Types of intermittent fasting for fertility

Not all intermittent fasting styles affect fertility the same way. Some approaches appear gentler on reproductive hormones, while others can be too stressful for a body that’s trying to ovulate consistently. If fertility is part of the goal, the details really matter.

Time-restricted feeding (TRF) and fertility

Time-restricted feeding is the most studied fasting approach when it comes to hormones and reproductive health. Research suggests that a 10-hour eating window tends to strike the best balance between metabolic benefits and hormonal stability. A 2020 study for Cell Metabolism found that a 10-hour TRF window supported insulin sensitivity without negatively affecting reproductive hormone patterns in women.

Part of the time-restricted eating’s effect could come down to why someone is following this eating plan. For example, if someone is doing it for weight loss purposes, particularly in an attempt to boost their fertility by losing weight, it may not be the best plan.

With that being said, weight loss is not the only reason someone may be interested in time-restricted eating. If you’re a fan of it and find it works well for your body and lifestyle, there’s no hard evidence to suggest it will affect human fertility, so don’t feel like you absolutely need to change your approach or fear that a history of time-restricted eating has irrevocably damaged your odds of getting pregnant.

For fertility, TRF ultimately works best when meals are regular, calories are adequate, and the window is consistent day to day. Think earlier dinners, not skipping meals entirely.

Alternate-day fasting (ADF) and fertility

Alternate-day fasting is generally considered too extreme for reproductive health. This approach creates large swings in energy availability, which can interfere with hormone signaling involved in ovulation. A 2017 study for the British Medical Journal found ADF difficult to sustain and no more beneficial than steady calorie intake for metabolic outcomes. For people trying to conceive, most experts advise against ADF due to its potential to disrupt cycles and increase physiological stress.

“We know that being overweight or obese can increase [the] likelihood of infertility,” explains James Nodler, MD, reproductive endocrinologist and site director for the CCRM Houston Medical Center. “Also, studies in humans have shown that intermittent fasting is not effective for long-term weight loss.”

The 5:2 diet and fertility

The 5:2 diet may be a better fit for fertility, particularly for people with PCOS. You eat normally 5 days a week and reduce calories on 2 nonconsecutive days, which limits prolonged restriction. A 2025 review for Metabolism Open found this approach (or TDF) may help improve insulin sensitivity and androgen levels in women with PCOS. It’s also often easier to maintain than daily restriction, which can matter for hormonal consistency over time.

The fertility diet: What really matters

When it comes to fertility, what you eat consistently matters far more than when you stop eating. Hormones rely on steady fuel, key nutrients, and enough overall energy to function well. That’s why most fertility research points back to dietary patterns, not eating windows.

One of the strongest bodies of evidence supports a Mediterranean-style diet. Information shared by EmbryoLab highlighted that “the Mediterranean diet can improve fertility by reducing the risk of conception difficulties, while it may help alleviate symptoms in women with premenstrual syndrome or endometriosis.”

That emphasis on nourishment over restriction is echoed by fertility specialists in clinical practice.

“I recommend a balanced diet following the Mediterranean model with half of the plate being vegetables with every meal, a quarter of the plate being lean protein, and a quarter of the plate whole grains with any meal,” Dr. Nodler explains. “We try to limit red meat and pork, and eat more fish or plant-based proteins like beans, lentils, nut seeds, and tofu.”

If intermittent fasting fits into your life, it should support this foundation, not replace it. Fertility tends to thrive on consistency, adequacy, and nourishment that doesn’t feel like a constant negotiation.

Intermittent fasting while TTC: What you need to know

Intermittent fasting isn’t a magic fertility tool, but for some people, it can fit into a bigger, supportive picture. It tends to make the most sense for those with PCOS or higher body weight, where blood sugar balance and hormone regulation are part of the fertility puzzle. For people who are already at a healthy weight with regular cycles, more caution is needed, since restrictive eating can quietly interfere with ovulation and cycle consistency.

If you choose to try intermittent fasting while trying to conceive, gentler is better. A longer eating window, regular meals, and nutrient-dense foods matter far more than pushing through long fasts. If you notice changes like irregular cycles, low energy, poor sleep, or increased stress around food, those are signs to pause and reassess. Your body’s feedback is part of the data.

The bottom line? If you love intermittent fasting and you don’t want to give it up, that’s probably just fine. With that being said, you may want to chat with your doctor about whether or not it’s a good option for you personally.

Dr. Nodler sums it up best: “I think that this is a good reminder to maintain healthy nutrition while trying for pregnancy and in pregnancy.”

Fertility usually does best with consistency, enough fuel, and an approach that feels supportive rather than stressful.