Some women are saying yes; here's what science knows about the keto-PMS connection.

By Isadora Baum and Maggie O'Neill
Updated: May 07, 2019

It's easy to see why the ketogenic diet continues to be so trendy. It can lead to weight loss, and followers get to eat the high-fat foods just about every other eating plan discourages. (A refresher: The keto diet restricts your daily intake of carbohydrates to about 5% and increases fats to about 75% of your daily calories, with the rest coming from protein.)

But some women are reporting yet another keto diet benefit: They claim it can help fight some of the PMS symptoms that do a number on your brain and body during your pre-period week. To be clear, there is no research outlining the exact effects of the keto diet on PMS symptoms.

But any new supposed benefit of the keto diet catches our interest, so we ran it by an expert. What we found is that the keto diet might do more harm than good when it comes to alleviating PMS. Here's how that can happen.

The keto diet can make constipation worse

Constipation is a classic PMS symptom. One way to manage this symptom is to increase your fiber intake. But you likely won’t be doing that on the keto diet. “The keto diet lack of fiber can only further enhance that problem for certain women,” nutritionist Keri Gans, RDN, tells Health.

Mayo Clinic says dietary changes can be used to manage PMS symptoms. “Choose foods high in complex carbohydrates, such as fruits, vegetables, and whole grains,” Mayo Clinic advises. This is obviously a problematic treatment for anyone on the keto diet, which restricts the amount of carbs you eat.

The keto diet can cause bloating

Many women report feeling bloated while experiencing PMS. “Premenstrual water retention is likely caused by fluctuations in your hormones. Your diet also might play a role,” Mayo Clinic explains.

Gans says that feeling bloated and being constipated sort of go hand-in-hand. “They’re almost connected,” she explains. In fact, bloating is a common cause of constipation, Johns Hopkins Medicine reports. That said, the dietary changes that can help you stay regular during PMS can also help you feel less bloated. But they're pretty much off-limits if you're doing the keto diet.

RELATED: Does the Keto Diet Cause Hair Loss? We Asked an Expert

Keto might make you more irritable

PMS sometimes puts you in a crabby state of mind. Tension, anxiety, crying spells, anger—most of us have been there. Following a diet as restricted as keto could add to the stress and make PMS mood swings even worse.

“You’re in a bad mood when you’re PMSing," says Gans. "Just the strain, the stress [of a restrictive diet]—that’s only going to make you more unhappy. It’s an emotional toll. Any restrictive diet is going to [cause you stress] when you’re PMSing.”

You may also feel super fatigued

Fatigue is a symptom of both the keto diet and PMS. The reason for your exhaustion on keto comes back to a lack of carbohydrates. “Remember, the keto diet’s eliminating almost all carbohydrates, our preferred fuel. As a general rule, carbs are our body’s preferred source of energy. [The diet] would only, then, lead to fatigue,” Gans says.

The keto diet might help with your breakouts

Now that we’ve explained how the keto diet can make your PMS symptoms worse, we’ll throw keto fans a bone: Since the diet requires that you eliminate many processed foods that have tons of sugar, it could lessen the severity of your PMS-induced breakouts.

RELATED: 5 Long-Term Health Risks of Going Keto

“The keto diet is eliminating refined sugars,” Gans says. “Menstrual acne, a flare-up of blemishes every month that coincides with menstruation, is fairly common. And according to the American Academy of Dermatology, “Scientists believe that following a low-glycemic diet may reduce acne because this diet eliminates spikes in your blood sugar.”

So will the keto diet ease or worsen PMS?

While we can’t tell you whether or not the keto diet is right for you, we can say that it appears to intensify a number of PMS symptoms women struggle with. That said, we’re here for any and all natural acne remedies as long as they're safe. If you have any questions about whether the keto diet is right for you, consult a nutritionist. You can also take any questions about PMS to your ob-gyn.

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