the art and science of taking care
Health | Beauty | Fitness | Nutrition

Can the Keto Diet Affect Your Period?


Diet changes can have a big effect on the menstrual cycle.


If you somehow haven’t heard about the keto diet yet, here’s a crash course: It’s a not-so-new diet, originally developed for treating epilepsy, that involves limiting your intake of carbs and loading up on fats, such as butter and meat. And while it seems counterintuitive at first glance, it can be a surprisingly effective—if not exactly sustainable—means of losing weight. This may sound appealing when you’ve got basically no free time, but drastically changing your diet can affect your body, including your reproductive system and, yes, your menstrual cycle. Consider this your guide to the connection between the ketogenic diet and your period.

First, it’s important to know that any type of weight loss has repercussions throughout the entire body. “The first thing that's affected by any rapid weight changes is a woman's menstrual cycle,” says Adeeti Gupta, MD, a board-certified ob-gyn and the founder of Walk In GYN Care in New York, NY. “Women may either get irregular, heavy bleeding or start skipping their periods, while a long-term underweight situation can lead to no periods at all.” That’s because when weight changes are extreme or sudden, as is the case with strict diets, it can affect the entire hormonal pathway, according to Gupta — which will obviously be a problem if you’re trying to get pregnant. As hormones control your menstrual cycle, it’s no surprise that it’s likely the first change you’ll notice.

And not eating enough calories regularly, no matter the diet, can always cause you to miss your period. Overall, if your diet “is causing you to consume too low a calorie amount, you might develop amenorrhea, or cessation of your menstrual cycle,” says nutritionist Keri Gans, RD. The same goes if your diet is off-balance. A well-rounded diet is essential to keeping your menstrual cycle on schedule, and that includes having the right proportions of carbs, fats, and proteins—something the keto diet throws off.

“However, there is no clear percentage defined for the exact amount of carbs needed for women to maintain normal functions,” Gupta explains. What is clear, though, is how much body fat you need to have your period: 15%. “If the body fat falls below that, then women may not get periods and have other conditions such as bone loss, hot flashes, etc,” she adds.

If you’re following the keto diet and notice changes to your menstrual cycle—whether it’s become irregular or your period has disappeared altogether—it’s worth taking seriously. “Start balancing out your diet and seek a gynecologist,” Gupta suggests. “You will need to check your hormone levels, blood counts, and may need an ultrasound as well.” And if you already have irregular periods, proceed with caution with this diet. “I don't like to say ‘Avoid altogether,’ but I would keep it within limits and avoid very rapid weight loss and extremes of diet changes,” Gupta advises. (And if you’re a new mom who’s breastfeeding, here’s what you need to know.)

Interestingly, one very small study suggested that a ketogenic diet low in carbohydrates could actually improve weight, testosterone levels, and fasting insulin in women with obesity and polycystic ovarian syndrome (PCOS). In it, 11 women with a BMI in the overweight or obese range and a clinical diagnosis of PCOS limited their intake of carbohydrates to 20 grams for 24 weeks. The five women who completed the study experienced significant improvements in a number of health markers.

But this may not be keto so much as the diet. “Weight loss by any method improves the symptoms of PCOS,” Gupta says. “PCOS is a condition where being overweight is a factor as well as a result, so rapid weight loss by any method improves the symptoms.” She’s a fan of more balanced diets for weight loss.

If you’ve been intrigued by the keto diet trend, or have questions about how any new diet might be affecting your period, talk to your doctor, who can help you work to find the right weight management program for your body.

Get more great health and wellness stories at