Why am I so hungry before my period?

Feeling hungrier in the week or so before your period is common, and it isn't a willpower problem. Studies find that women tend to eat a little more in the luteal phase, the stretch between ovulation and your next period, with appetite and cravings highest in the last few days. The most useful response is to plan for it: more protein and fiber at lunch, a planned afternoon snack, and room for both in your week's calories.

Below is what the research shows, what's known (and not known) about why it happens, and a simple plan for this week.

How much hungrier do women get before a period?

A little, on average, though it varies a lot from woman to woman.

The best summary so far is a 2024 meta-analysis in Nutrition Reviews. The researchers pooled 15 datasets covering 330 women and found they ate more in the luteal phase than in the follicular phase (the stretch from your period to ovulation). The crude average difference was about 168 calories a day, roughly one snack's worth.

The authors were open about the weak spots:

• Only 8 of the 15 datasets found a clear difference on their own.
• Every study relied on women recording what they ate, which is easy to get wrong in either direction.
• Only 3 studies confirmed cycle phase with more than one method, and the authors note that a single method is now considered insufficient.
• The studies only included women aged 18 to 45 with a BMI between 18.5 and 25 and no history of disordered eating, so the results may not describe everyone.

The BioCycle study adds detail on timing. It followed 259 women with regular cycles for up to two cycles, using home fertility monitors to time each visit. Appetite and cravings for chocolate, sweets and salty foods were all significantly higher in the late luteal phase, the last days before a period, than during the period itself, the follicular phase or around ovulation. Protein intake was highest in the mid-luteal phase. Interestingly, total calories in that study were only slightly higher mid-luteal, and the difference wasn't statistically significant.

So the honest picture is this: for many women the hunger is real, it tends to build toward the end of the cycle, and the size of it is modest. Think one extra snack, not a different way of eating.

Why it happens: what's known and what's a guess

Estrogen seems to put a brake on appetite

A 2022 review in Frontiers in Endocrinology describes estradiol, the main form of estrogen, as a hormone that tends to lower food intake. In clinical studies, women eat least around ovulation, when estradiol surges, and more in the early follicular and luteal phases. The drop around ovulation comes from smaller meals rather than fewer of them.

The luteal phase has a different hormone mix. As the Nutrition Reviews authors describe it, estradiol dips after ovulation and then rises to a smaller second peak, while progesterone climbs to its highest level by the middle of the phase. Both then fall before your period starts. So estrogen is no longer working alone.

Progesterone may push the other way

The leading idea, as the BioCycle authors put it, is that estrogen suppresses appetite and progesterone stimulates it. The evidence for progesterone's part is thinner than most articles suggest, and much of it comes from rodents. In the studies the 2022 review describes, giving estradiol to rats whose ovaries had been removed brought their eating back to normal, but progesterone did not. The Nutrition Reviews authors suggest progesterone may raise appetite directly or blunt estrogen's effect, but they call its role less understood and point out that a rat's cycle lasts only 4 to 5 days, which makes it a rough model for a human one.

Do you burn more calories before your period?

You'll see confident claims that your metabolism speeds up before your period. A 2020 meta-analysis in PLOS ONE pooled 26 studies with 318 women and found resting metabolic rate was slightly higher in the luteal phase, a small effect. When the authors looked only at studies published since 2000, the difference shrank further and was no longer statistically significant. The authors also flag small samples and a risk of bias in how both the cycle and metabolism were measured.

So your body may burn a little more at rest in the luteal phase, but don't count on it to cancel out an extra snack every day.

Blood sugar and serotonin

You'll also read that blood sugar swings or a dip in serotonin drive premenstrual hunger. The 2022 review notes that some studies have found higher insulin resistance in the luteal phase, even in healthy women, and that lab research links estradiol, insulin and serotonin to binge eating. The authors say the insulin change "could partially explain" differences in eating across the cycle. That's a reasonable idea worth more study, not a settled explanation.

What appetite tends to do across your cycle

These are averages from the studies above. Your own pattern may differ, which is why tracking it (below) is worth a couple of months.

What to do this week

1. Find your place in your cycle

Count from day 1 of your last period. The luteal phase covers roughly the week or two before your next one. For the next two cycles, rate your hunger from 1 to 5 each day and mark your period dates. The NHS suggests keeping a symptom diary for at least 2 cycles, and it turns "I think I'm hungrier" into a pattern you can plan around.

If you use hormonal contraception or your periods are irregular, your pattern may not follow the textbook, so go by what your notes show.

2. Build lunch around protein and fiber

If the hunger hits mid-afternoon, lunch is the place to start. In a 2016 meta-analysis in the Journal of the Academy of Nutrition and Dietetics, higher-protein meals and snacks raised fullness ratings more than lower-protein ones over the following hours. The authors add a fair warning: those were tightly controlled lab studies, and fuller doesn't automatically mean eating less later. So treat it as a sensible, low-risk move, not a guarantee.

Pair the protein with a fiber-rich carbohydrate, such as beans, lentils, whole grains, fruit or vegetables. A few lunches that do both:

• Lentil soup with a slice of whole-grain bread and a pot of Greek yogurt
• A grain bowl with chicken or tofu, black beans, roasted vegetables and salsa
• Tuna or white-bean salad with whole-grain crackers and an apple
• Eggs on whole-grain toast with a big side salad

Our guide to how much protein women need covers how much to aim for each day and how to spread it across meals.

3. Plan an afternoon snack

For PMS, the NHS suggests you may find frequent smaller meals, every 2 to 3 hours, work better. On hungry days, a planned snack around 3 or 4 pm does a similar job. Decide what it is in the morning, so you're choosing before you're starving. Some ideas:

• Greek yogurt or cottage cheese with berries
• An apple or pear with a piece of cheese
• Hummus with carrots, peppers and a few whole-grain crackers
• A handful of roasted chickpeas or edamame
• A glass of milk or fortified soy milk with a banana

For more on cravings, calcium and bloating in these weeks, see what to eat in the luteal phase.

4. Choose your treat on purpose

Cravings for chocolate, sweets and salty food are among the most consistent findings in the BioCycle study. Wanting them isn't a failure. Pick a portion you'll enjoy, ideally after a meal, and eat it sitting down. Planning it means you decide the portion, instead of the craving deciding for you.

5. Count it in the week, not the day

If you're eating in a calorie deficit, an extra 150 to 200 calories on five to seven days adds up to roughly 750 to 1,400 calories across the week. You have two calm ways to handle that:

• Accept a smaller deficit for those days. Keep your plan, add the snack, and let the week run a little closer to maintenance. One slower week doesn't undo the ones before it.
• Keep the weekly total. If you track, trim a little on the days your appetite is lowest, often around ovulation, rather than squeezing the hungry days. Don't let any single day drop very low to make up for it.

Our guide to a calorie deficit for women explains how to set a moderate deficit and why very low intakes backfire. And if the scale climbs that week, read weight gain before your period before you change anything.

If you've ever eaten very little all day to "be good" and then found yourself in the cupboard at 9 pm, this plan is the alternative: eat enough earlier, so the evening isn't a fight.

If you'd rather not track the timing yourself, HerShape estimates your cycle phase from your last period and cycle length, then plans your meals and training with it in mind.

When to talk to a doctor

Premenstrual hunger on its own is normal. Check in with a doctor if:

• It's affecting your daily life, or changes like these haven't helped. That's when the NHS suggests seeing a doctor about PMS. Bring your symptom diary.
• Eating feels out of control, or your mood drops sharply before your period. The NHS lists overeating among the symptoms of premenstrual dysphoric disorder (PMDD), a more severe form of PMS that also brings intense anxiety, anger or low mood. A doctor can help. If you ever feel unsafe or have thoughts of suicide, contact emergency services or a crisis line right away.
• Big appetite changes don't follow your cycle, or come with other changes you can't explain.
• You have a condition that changes the picture. That includes PCOS, endometriosis, pregnancy or a late period, the months after giving birth, perimenopause or a history of disordered eating. A clinician or registered dietitian who knows your history is the right person to shape your plan.

The bottom line

Being hungrier before your period is common and usually modest, around a snack's worth a day on average. The leading explanation is the shift in estrogen and progesterone after ovulation, though the details aren't settled, and claims about metabolism, blood sugar and serotonin are less certain still. Plan for it rather than fight it: protein and fiber at lunch, a snack you chose in advance, a treat you actually want, and a weekly view of your calories. Track your hunger for two cycles and let your own pattern guide you.

Sources

• Nutrition Reviews (2024): The Effect of the Menstrual Cycle on Energy Intake: A Systematic Review and Meta-analysis
• European Journal of Nutrition (2016): Changes in macronutrient, micronutrient, and food group intakes throughout the menstrual cycle in healthy, premenopausal women
• Frontiers in Endocrinology (2022): The importance of estradiol for body weight regulation in women
• PLOS ONE (2020): Effect of menstrual cycle on resting metabolism: A systematic review and meta-analysis
• Journal of the Academy of Nutrition and Dietetics (2016): The Effects of Increased Protein Intake on Fullness: A Meta-Analysis and Its Limitations
• NHS: Premenstrual syndrome (PMS)