The high-fat, extremely low carbohydrate “keto” diet, which has gained popularity over the past several years, has been linked to weight loss and other health advantages, but it can also have an odd effect on your menstruation. Some women who follow the ketogenic diet experience irregular periods, while others claim that after starting the diet, they developed amenorrhea or the complete disappearance of their monthly cycle.
Amenorrhea appears to rank closely behind weight reduction as one of the most common negative consequences of the diet. According to one study, 60% of participants said the diet caused them to lose weight, while 45% of the female participants said their periods were irregular.
The Keto Diet’s Potential Impact on Periods
How come? It might be connected to rapid weight reduction. “Cycle irregularities can develop if someone is cutting too many calories,” explains Kristen Kizer, RD, of Pura Vida Behavioural Nutrition in Canberra, Australia.
Even though it has been demonstrated that the ketogenic diet can result in rapid weight loss, this can occur with any diet. According to earlier studies, after a year of following a low-calorie ketogenic diet, the majority of study participants had lost at least 10% of their starting weight. By forcing your body into a metabolic state known as ketosis, the keto diet can help you lose weight quickly.
Low carb intake has also been associated with irregular periods, according to John Thoppil, MD, a board-certified obstetrician-gynecologist at River Place Obstetrics and Gynecology in Austin, Texas, but he notes that the majority of the evidence for this association is anecdotal or comes from tiny studies. He concurs that alterations in your period are probably caused by weight loss rather than by keto in particular.
How Do Hormones React to the Keto Diet?
The disappearance or irregularity of menstruation is likely due to hormonal changes. According to Dr. Thoppil, a pulsatile release of hormones from the brain is necessary for having a regular period. Any stressor, including rapid weight loss events and intense activity, can interfere with the pulsatile release necessary for the regular hormone release choreography that allows for regular menstruation. According to a study that was published in September 2018 in the Journal of Obesity and Weight Loss Therapy, women’s hormonal systems were upset by the keto diet.
Estrogen, which controls the menstrual cycle, is one of the key hormones at work here. According to a board-certified cardiologist and nutritionist Luiza Petre, MD, based in New York City, as weight decreases, estrogen levels do as well. Previous studies have shown that the levels of the estrogen hormones estrone and estradiol declined by 5.7 and nearly 10 percent, respectively, when individuals lost an average of 17 pounds. The authors of the study point out that calorie restriction and exercise-induced weight loss dramatically reduced estrogen levels.
The gonadotropin-releasing hormone is another hormone that appears to interfere with menstruation regularity. (GnRH). Follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which stimulate ovarian production of estrogen and progesterone and, consequently, ovulation, is produced by the pituitary in response to the signal GnRH.
A tiny study indicated that obese PCOS women who followed the ketogenic diet for 12 weeks dropped a substantial amount of weight and had a decline in the ratio between LH and FSH, which indicates a more favorable balance between the two hormones. The study was published in the Journal of Translational Medicine in February 2020. Another small study with 25 obese and PCOS patients discovered that the ketogenic diet benefited the subjects’ metabolic and ovulatory dysfunction. This result was published in the October 2022 issue of Nutrients.
According to a May 2018 Endotext article, changes in body composition (such as those brought on by weight reduction due to the keto diet or another diet) can affect GnRH levels.
Reduced estrogen results after GnRH disruption and these modifications can interfere with ovulation and produce amenorrhea.
If Keto Does Affect Your Cycle, How Concerned Should You Be?
It can be problematic when estrogen levels are declining. However, Thoppil notes that the increased risk of bone loss is a long-term health worry. “Lower estrogen levels have certain side effects that go along with that, [such as] vaginal dryness,” she says. The Mayo Clinic states that osteoporosis is a documented side effect of amenorrhea. He occasionally advises patients to take a natural estrogen supplement to safeguard their bones. One type of natural estrogen supplement is estradiol (estrace).
Obviously, irregular periods and decreased estrogen levels can also impact fertility. But according to Thoppil, “if you’re not worried about getting pregnant, and thus ovulation is not the end all be all, [it’s not much to worry about] from a pure health standpoint.” He advises consulting your doctor if you’ve previously had regular cycles and have continued to notice anomalies for three to six months.
How to Return to a Regular Period While on Keto
According to Thoppil, the majority of people have a “happy weight” over which they’ll restart regular periods. He acknowledges that it’s quite individualized and may require some trial and error. The first thing, he advises, is to try adding a little weight to see if it helps. That can entail raising your daily caloric intake by 250 calories or reducing the intensity of your intense workouts. According to Thoppil, “For some, 5 pounds would make a difference and restore the menses.”
The maximum daily carbohydrate intake for maintaining ketosis varies for each person and is often between 20 and 50 grams, according to Dr. Petre. Alternatively, she advises thinking about keto cycling, which is keeping your body in ketosis for five days before consuming more carbs for two days.
When you reach that threshold weight will determine how long it takes for things to return to normal. Thoppil said, “It could happen as soon as this month.” However, each person’s body reacts differently and has varied nutritional requirements.
How Keto Could Aid with Period Restoration
Interestingly, the opposite may also be true: Overweight people who lose weight on keto may see a return in their periods. Success with keto can make your cycle vanish. According to Thoppil, weight gain frequently causes ovulation problems. There are definitely some ketogenic individuals that resume menstruation. In fact, he asserts that there are probably just as many individuals in this group as there are those who have cycle loss.
The Final Word on Keto and Your Period
Remember that your diet might not even be to blame. According to the Eunice Kennedy Shriver National Institute of Child Health and Human Development, missed periods can be a sign of a more serious health problem, such as hormone imbalance, genetic abnormalities, or polycystic ovarian syndrome (PCOS). Losing your cycle, whether while on keto or not, is a solid cause to see your doctor, according to Kizer.