This is how intermittent fasting can affect your mood

If you’ve ever given intermittent fasting a shot, you’re likely familiar with some of the benefits of time-restricted eating after you’ve been doing it for a while: Better sleep, improved energy, and more balanced blood sugar levels. So this means you should feel like you’re walking on sunshine and rainbows, right? Well, not exactly.

Here, women across the country get candid about how IF has affected their mood, from the start and also months in, and Beth Westie, DC, a women’s health expert and author of the book The Female Fat Solution: Achieving Lasting Weight Loss By Getting Your Hormones To Work For You explains the why behind it all.

Keep reading for everything you need to know about how intermittent fasting affects mood.

The first few weeks can make you, well, moody

First things first: It’s important to know that there are a few different methods of fasting. Some people opt for the 16:8 method (fasting for 16 hours and eating during an eight-hour window), while others prefer a full-on 24-hour fast one day a week. Regardless of the method they try, women in particular often notice that IF has an obvious impact on their daily mood, for better or worse.

Dr. Westie notes that the mood shifts she sees when women first start fasting are often a result of a physical reaction that leads to an emotional reaction. “Take blood sugar, for example,” she says. “The brain functions off sugar. When your blood sugar drops from lack of nutrients, your brain is no longer functioning at full capacity. This can be seen as an emotional response, or a woman can be seen as ‘crabby’ when really she’s having a physical response that manifests as an emotional response.”

Indeed, Westie is onto something when she references those difficult first few days and weeks. Stacey Leasca, a 33-year-old journalist who lives in Venice, California and practices the 16:8 method, found that when she first started fasting, her mood was all over the place. “I never realized how much of my day revolved around what meal I was going to eat next,” she admits. “I was anxious and all over the place for the first three days.”

Sarah, a 26-year-old woman living in Miami, Florida who also practices the 16:8 method, said her first few weeks of fasting were pretty unbearable mood-wise. “I absolutely hated it at first,” she says. “I had brain fog, I was weak and hungry, and it was really hard to even wait two hours to eat after I woke up.” In these ways, it’s a bit similar to keto flu.

Saying goodbye to bloat and hello to crazy energy

Before you decide to ditch the idea of IF altogether, consider this: There is a light at the end of the tunnel. After Leasca got through those initial 72 hours, she found that she felt like an entirely different person—this time in a good way.

“I don’t even realize I do it anymore, it’s just become second nature,” she says. “I still eat roughly the same amount of calories I did before, but now that my body has time to actually digest I feel way less bloated, I have insane energy in the mornings, and I no longer crash in the afternoon. I give fasting all the credit for this shift, because I haven’t changed anything else about my routine.”

Westie notes that Leasca’s reaction makes sense. She says that while not all fasting methods are beneficial for women’s bodies—fasting for a full 24 hours can be rough for hormone levels, which is why the majority of women go for the 16:8 method—if done correctly and in a way that honors the body, fasting inevitably leads to some noticeably amazing shifts in mood.

“The first couple months may be tough, but eventually the body begins to become less insulin resistant,” Westie explains. “A woman will also notice her digestive and immune systems functioning better, and serotonin levels improved. Due to all of these things, women will often notice an improvement in mood.”

Chelsea Barbee, a 23-year-old women who is based in Atlanta, Georgia, found that once she got over the initial hump, IF led to a clear-headedness she had never experienced before. “I feel so much clearer throughout the day, and I definitely don’t suffer from feelings of grogginess feeling anymore,” she says. “I’ve never been much of a morning eater, and now I find that if I do eat first thing in the morning, I become nauseous. Intermittent fasting really just makes the most sense with my body’s wants.”

Honoring what your body needs

While IF is a great tool to have in your back pocket, Westie cautions against ignoring signals from your body. “Each woman is going to have a different reaction to fasting depending on where they are hormonally and how much stress they have in their life,” she explains. “A prolonged negative emotional reaction is something to watch out for, as it means the body isn’t reacting well to this style of eating.”

Thirty-two year old Michelle Cady, a New York-based health coach and author of Self-Care In The City, finds that while in general her body reacts well to the 16:8 method of fasting, there are times when she needs to eat first thing in the morning—and that’s okay.

“On mornings when I’m stressed or have a ton on my schedule that day, I do make the conscious decision to eat breakfast,” she says. “I don’t believe it’s a good idea to fast while you’re also super stressed, because your body thinks you’re in a famine.”

Cady adds that this decision isn’t just schedule-based: It also has to do with how she feels. “If I feel off, light-headed, unmotivated, or unable to focus on my work, I eat.” If you’re restricting your diet for the sake of restriction, it could be a sign of disordered eating. The number one key is to truly listen to your body.

While the consensus may be that regular fasting ultimately leads to more energy, less brain fog, and a more level mood overall, the truth is that everyone’s body is different. So do your best to honor yours.

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