Why some experts don’t recommend intermittent fasting if you’re trying to get pregnant
Intermittent fasting is a popular eating plan, but some experts warn that it might be bad for women's hormones and fertility. Here's what you should know.
Why some experts don’t recommend intermittent fasting if you’re trying to get pregnant
Intermittent fasting is a popular eating plan, but some experts warn that it might be bad for women's hormones and fertility. Here's what you should know.
Forget about simply cutting processed foods or carbs from your diet: Celebs like Hugh Jackman and Kourtney Kardashian reportedly aren’t eating much—if at all—some days. Known as intermittent fasting (IF), the goal of the buzzy eating plan is to speed up metabolism, encourage healthy weight management, and improve overall health by following certain time-specific restrictions on eating. But if the idea of severely cutting calories or skipping meals on some days sounds iffy to you, there’s good reason to be hesitant—especially if you’re a woman.
The calculations on IF benefits, however, may change for women. “In my patients, I’ve seen a lot of females who can’t go above 18 hours of fasting, while the guys can do three-day water fasts,” says Ruvini Wijetilaka, MD, a board-certified internal medicine physician at Parsley Health in New York City. “I’m not saying all fasting is bad. But severe caloric restriction in IF is not beneficial fertility-wise.”
As it’s presented in high school health class, pregnancy seems pretty straightforward: egg plus sperm equals baby. But conception involves a delicate balance of hormones and timing that can be affected by everything from your weight to what you eat (or what you’re not eating). For example, having a very high BMI can mess with a person’s hormone balance, leading to irregular ovulation, explains Aaron Styer, MD, a reproductive endocrinologist and a founding partner and co-medical director of CCRM in Boston. People who are underweight can also struggle to get pregnant. “The female pituitary gland can sense calorie intake. Below a certain level, it can create a signal from the brain for ovulation to be reduced or absent,” says Dr. Styer.
Want to know more about IF? Check out this guide from a top registered dietitian:
Similarly, intermittent fasting might affect levels of the hormone leptin, explains Dr. Styer. Leptin is produced by the body’s fat cells and controls not only your metabolism but levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), the hormones that regulate ovulation. Too little leptin, and there might be issues with fertility down the road. “It could possibly sub-optimize the ability to conceive. But it’s not confirmed,” he says. Dr. Wijetilaka adds that one small study in mice showed that very severe caloric restriction brought on by some forms of IF shrunk ovary size and decreased LH and FSH levels. But this was a study in mice and thus isn’t a certainty in humans.
If you do conceive, IF may not foster the ideal conditions for a fast-growing baby, either. “Pregnancy requires lots of resources. You don’t want to cause undue stress from restricting calories,” says Dr. Styer. People who are pregnant actually need to be eating more calories per day—340 extra calories per day in the second trimester, and around 450 extra per day during the third trimester. Trying IF, or sticking with it, during pregnancy should thus be put on hold until you can talk to your doctor about it and see what they think.
It’s important to note that this is mostly a theory—there’s not a ton of research out there on humans that has looked into IF’s potential effect on fertility. There are also many different ways to do IF, some of them with more potential risks than others. Both Dr. Wijetilaka and Dr. Styer suggest steering clear of caloric restriction types of IF like 5:2 (eating 500 calories per day a couple of times per week), alternate-day fasting (capping calories at 500 every other day), and 24-hour fasts (not eating at all for one or two days per week) if you’re trying to get pregnant. However, time-restricted eating plans like 16:8, where you eat whatever you want during a set eight-hour period during the day and fast for the remaining 16 hours, may be safer for fertility, Dr. Wijetilaka says. She adds that while fasts over 16 hours are risky, she generally recommends a 12-hour fast to give the body and metabolism a rest.
Dr. Styer agrees that time-restricted eating is safer, but he still doesn’t recommend IF for women who are trying to get pregnant. “The female pituitary gland can be sensitive to caloric intake and diet in general,” he says. But don’t sweat it if you’ve already given IF a go in the past or if you want to try it out and aren’t planning on conceiving in the near future. “Your body is resilient. I don’t see risks for a future pregnancy,” Dr. Styer adds.
As with all eating plans, it’s a good idea to talk to your doctor or dietitian about intermittent fasting before diving in, especially if you’re thinking about pregnancy in the near future. While maintaining a healthy BMI is important for fertility and pregnancy, Dr. Styer says, IF might not be the way to get there. “Intermittent fasting is intriguing, and many people have lost weight successfully. But studies are limited in fertility and reproduction,” he says.
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The first thing you should probably know about me is that I generally steer clear of wellness pills and powders. As a health writer and editor who's covered supplements for years, I've acquired a wary view of these products that tend to make bold-yet-vague health promises while being only very loosely regulated by the FDA.
Carla Hernandez, RDN, Los Angeles-based registered dietitian
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*Steps off soapbox* Now that's out of the way, I'll admit I've been curious about AG1 (formerly Athletic Greens) for a while. Friends sing its praises, and you don't have to look hard to find positive AG1 reviews across the internet. So I gave it a go. Here's my experience taking AG1 for a few weeks, plus insight from two registered dietitians on the pros and cons of the greens powder, who might benefit from it, and who should steer clear.
Good Manufacturing Practices (GMP) certified facility
Pleasant taste (no artificial sweeteners)
Free of many common allergens
Convenient
Offers a money-back guarantee
Cons:
Expensive
Doesn’t contain vitamin D or iron
Health claims are somewhat vague
What is AG1?
Backing up for a minute, in case you haven't seen the green drink all over social media like I have, here's the breakdown: AG1 is a powdered nutritional supplement that contains 75 vitamins, minerals, probiotics, and adaptogens. To take it, you mix a scoop of the powder into 8 to 12 ounces of cold water, shake, and ideally drink on an empty stomach (the brand recommends taking it daily, first thing in the morning).
The powder can also be mixed into other cold beverages, like smoothies or juices, but the brand warns against combining it with hot drinks because it might make the ingredients less effective.
If you've ever taken a multivitamin, you're probably thinking 75 ingredients is a lot. And you're right. So let's take a closer look.
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Ingredients
One scoop of AG1 (that's 12 grams) has 50 calories, 6 g of carbs, 2 g each of fiber and protein, and less than a gram of sugar.
Here are the nutrients you get per serving:
Vitamin A: 555 mcg RAE (62% DV)
Vitamin C: 420 mg (467% DV)
Vitamin E: 83 mg (553% DV)
Thiamin (vitamin B1): 3 mg (250% DV)
Riboflavin (vitamin B2): 2 mg (154% DV)
Niacin (vitamin B3): 20 mg NE (125% DV)
Vitamin B6: 3 mg (176% DV)
Folate: 680 mcg DFE (170% DV)
Vitamin B12: 22 mcg (917% DV)
Biotin (vitamin B7): 330 mcg (1100% DV)
Pantothenic acid (vitamin B5): 4 mg (80% DV)
Calcium: 118 mg (9% DV)
Phosphorous: 130 mg (10% DV)
Magnesium: 26 mg (6% DV)
Zinc: 15 mg (136% DV)
Selenium: 20 mcg (36% DV)
Copper: 195 mcg (22% DV)
Manganese: 400 mc (17% DV)
Chromium: 25 mcg (71% DV)
Sodium: 45 mg (2% DV)
Potassium: 300 mg (6% DV)
What's all that mean?
Keep in mind: DV means the percent daily value, which reflects the recommended amount of a nutrient to consume each day, and it's based on a 2,000-calorie diet for healthy adults. You'll notice a pretty wide range of percentages on the above list. For example, the recommended amount of daily vitamin E is 15 mg1. AG1 has 83 mg, which is more than five times the recommended amount. It's much lower than the vitamin's tolerable upper limit of 1,000 mg per day, but it's good to take stock of what those percentages mean for you in relation to your existing diet.
Once we're past the vitamins and minerals, things get a little less clear. That's because AG1 contains four proprietary blends: a "superfood" complex, an herb and antioxidant blend, digestive enzymes, and probiotics. While the label shows the total grams per serving of each blend, it doesn't break it down further. So, for example, we don't know for sure how much spirulina or green tea extract is in there.
"You don't know how much of [those ingredients] are actually in the product," says Leah Murnane, RD, CSSD, LDN, board-certified sports dietitian and founder of Lettuce Eat Dessert. "And for the size of the scoop, it's hard to think that there would be enough of those items in there to actually offer a benefit,"
Health claims
The main claim AG1 makes is that "one scoop supports whole body health." The label also lists a slew of general health benefits, like "energy and focus," "stress and mood balance," "brain and nerve function," and "healthy aging."
If you read the label closely, you'll notice each of these claims appears with an asterisk. The caveat is that the FDA hasn't reviewed or approved any of these statements. As with other supplements, we're kind of just taking the brand's word that these are all true.
The research
There is some research to back up AG1's health claims, though. Over the past 15 years or so, the brand has commissioned a few scientific studies, including an observational study and a clinical trial. This is definitely admirable, considering many other supplements that say they're backed by research rely on low-quality animal or in vitro studies, or research done on individual ingredients.
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AG1's studies, on the other hand, looked at people using the actual product and found that those who took the supplement more than doubled their levels of healthy gut bacteria. What's more, folks who regularly took AG1 for three months reported positive effects on their energy levels, digestion, and overall sense of calm.
Still, these studies were ordered by the brand, so it's wise to take them with a grain of salt, Murnane says. Beyond that, she adds: "There's also not a ton of [knowledge about] how it's going to affect you long-term, just because it is such a relatively new thing within the last 10 to 15 years."
My experience taking AG1
After taking the supplement for a few weeks, here are the pros and cons of AG1 as I see them.
What I like about AG1
Third-party certified: First and foremost, I appreciate that AG1 is NSF Certified for Sport, which means the product has been independently tested by NSF (a well-respected name in the supplement-testing business) to ensure it actually contains the ingredients it claims on the label, in the amounts claimed, and that it doesn't have any extras not listed (like heavy metals or other contaminants). This kind of testing is voluntary, so the seal carries a lot of weight. AG1 is also manufactured in a facility that is Good Manufacturing Practices (GMP) certified, which adds another level of quality assurance.
Tasty: I was pleasantly surprised by the taste. As a greens powder, I assumed it'd be a little bitter, but it's got a pleasant pineapple-forward flavor courtesy of dried fruit powders. It also mixes into water easily, with no clumps, although the texture is a little bit chalky. I also love that there's no added sugar or artificial sweeteners, although it does contain stevia.
Convenient: This supp packs a hefty nutritional punch into one once-a-day product that's easy to take (aka, no pills to swallow). You do have to refrigerate the pouch after opening, but I like that there's a travel pack option—these single-serving packs are easy to throw in a gym or overnight bag, no fridge required.
Self-care boost: I was surprised how a three-minute morning ritual could feel like a self-care practice. Taking a beat out of my busy mornings (that mainly include making breakfast and packing lunches for other people) to drink AG1 gave me the sense that I was doing something good for me, which gave me a small sense of accomplishment that was a nice way to start the day.
Pick-me-up: Whether because of the natural sugars, B vitamins, or green tea extract (or maybe a combo of all three), I did feel a little burst of energy after finishing the drink — enough to delay my morning coffee, which I usually reach for ASAP. Still, I didn't notice any long-lasting effects on my energy throughout the day.
Money-back guarantee: The brand offers a 90-day money-back guarantee, which is just a nice thing to do. I didn't return my AG1, but I appreciate that it's a possibility for anyone who doesn't jibe with the product.
What I don't love so much
Expensive: AG1 costs more than many other greens powders or multivitamin products. A month's supply (30 servings) starts at $79 for the pouch and $89 for the travel packs. And that's with a subscription. Without one, it's $99 or $109, respectively. Either way, it's a hefty price tag that, for me, is a little hard to justify.
Nausea: The supplement is meant to be taken on an empty stomach for best absorption, but I had a hard time, well, stomaching it. I felt nauseated if I didn't eat breakfast within a few minutes of downing the drink. Of course, you don't have to take AG1 on an empty stomach, and Carla Hernandez, RDN, a Los Angeles-based registered dietitian with a focus on gut health, told me there may actually be a benefit to taking the supplement with food (which I started doing instead). "The digestive enzymes can help you digest the food," she notes. "And there are a lot of fat-soluble vitamins in this product, so a lot of those don’t necessarily get absorbed unless you’re taking it with fat."
Doesn't contain vitamin D or iron: These are two nutrients notably missing from AG1, but they're among the nutrients that women like me are most likely to be deficient 2 in. Nutrient deficiencies aren't common in the U.S., though, and I've personally never had blood work reveal low levels of either vitamin D or iron. And it's worth noting that AG1 also sells vitamin D3 drops that include vitamin K2 for better absorption.
Tips for taking AG1
Both Murnane and Hernandez say they've tried AG1 and generally think it's a quality supplement, although it's not for everyone. Here are their tips on taking it:
Don't use it to replace a healthy diet
AG1 can be a nice tool to have in your nutritional toolbox but, ultimately, it isn't a replacement for eating a well-balanced diet rich in fruits, vegetables, lean proteins, and whole grains. Rather, Murnane and Hernandez say it can occasionally help fill in the gaps when, say, you're traveling or you know you're going to have a busy day and won't be able to prioritize your nutrition like you normally do.
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Pay attention to your symptoms
If you decide to take AG1 because you're consistently low on energy or always dealing with GI issues like bloating, take the time to get to the bottom of the issue rather than treating your symptoms with a supplement. You could be dealing with a medical issue that's best treated under a doctor's guidance.
One issue Hernandez notes specifically is SIBO, or small intestinal bacterial overgrowth, where too much bacteria in the gut leads to symptoms like diarrhea, bloating, and abdominal pain. "The prebiotics in this product are great and necessary for a healthy microbiome, but for people with SIBO, it can exacerbate their symptoms."
Talk to your doctor first
Hernandez and Murnane encourage consulting your doctor before taking any new supplement, and especially one with as many ingredients as AG1. This goes double for anyone managing a medical condition or taking medication, or if you're pregnant or breastfeeding.
"Any product that has multiple herbs may potentially have some kind of interaction with medications," Hernandez notes.
Final thoughts
AG1 is a high-quality supplement with some research to back up its health claims. It's also tasty and a convenient way to fill in any nutritional gaps, especially for people who don't like to swallow pills. Still, it has a high price point and it's not a replacement for eating a well-balanced diet. If you're interested in trying AG1, check with your doctor first to make sure it's safe for you based on your medical history and any current medications you're taking.
National Institutes of Health Office of Dietary Supplements. (2021). "Vitamin E Fact Sheet for Consumers." https://ods.od.nih.gov/factsheets/VitaminE-Consumer/ ↩︎
Centers for Disease Control and Prevention. (2024). "About the Second Nutrition Report." https://www.cdc.gov/nutrition-report/about/index.html ↩︎
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Confession time: I love citrus—zesty limes squeezed on my tacos, fresh-squeezed orange juice on slow Sunday mornings, and the invigorating scent of grapefruit candles when I need to unwind. But when it comes to eating whole citrus fruits? Historically, not my thing. The mess of peeling, the sticky fingers, the rogue juice dribbling down my wrists—for me, most citrus has never been worth the (literal) squeeze.
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Then, one day, my roommate came home from the store with an oversized citrus I didn’t recognize. She told me I had to try a piece, while effortlessly peeling it in one smooth motion—no mess, no struggle. I skeptically accepted a slice, wondering what the big deal was.
To my surprise, the experience was completely sticky-fingers-free. And the taste? Unlike any citrus I’d had before—enormously sweet, impossibly juicy, and balanced with just a hint of tang. That was my first bite of Sumo Citrus®—and now, I understand why The Office actress Jenna Fischer planted a Sumo Citrus tree in her yard, John Mayer peeled it on TikTok, and it has its very own merch (kind of eyeing that beanie, TBH).
So, what’s earned Sumo Citrus this devoted following? Sumo is taking the sweetness on the road for you to experience it yourself with the Tastemonial Tour—and it’s making a special stop at House of Good during our Ultimate Citrus Experience pop-up from February 21 to 23. Stop by for the hype if you're in Los Angeles, and read on to find out how this one-of-a-kind fruit became a seasonal fruit fixation.
Sumo Citrus wasn’t just plucked from a tree one day and marketed as the next big thing—it’s the result of decades of careful cultivation, according to Sunnia Gull, AC Food’s vice president of marketing. First developed in Japan in the 1970s, it was naturally bred to combine the best traits of different citrus varieties—including the sweetness of mandarins, the juiciness of navel oranges, and the easy-to-peel skin of a satsuma.
Despite its popularity, growing Sumo Citrus is no easy feat. It takes years of expertise to perfect, and California’s Central Valley is the only place in the United States where it’s grown. Even then, farmers face unpredictable weather challenges, which means every piece of fruit that makes it to the store is a result of careful tending and patience.
The first thing you notice about Sumo Citrus is its size—it’s the largest variety of mandarins. The second? Its signature Top Knot®, a bump on top of the fruit that serves as an easier way to peel it. The skin practically lifts off, revealing plump, seedless segments that don’t leave your hands coated in juice and stubborn pith.
Every Sumo Citrus is guaranteed to be incredibly sweet, thanks to each being measured on the “brix meter,” to ensure it meets sky-high sweetness standards before hitting shelves, Gull says. For those who prefer their fruit without surprise sour bites, it’s a game-changer.
Beyond its chef’s-kiss flavor and finally-I-don’t-need-a-wet-wipe convenience, Sumo Citrus packs a *serious* nutritional punch. Each fruit contains 163 percent of your daily vitamin C, along with fiber, potassium, and a flavonoid called hesperidin, which has antioxidant benefits. Whether you’re looking for immunity support, a gut-friendly snack, or a natural energy source, it fits the bill. Bonus: It’s the kind of snack I can toss in my bag and eat in two minutes flat—way better than the sad granola bar that’s been in my purse for the past three months.
And while Sumo Citrus is made to eat straight out of the peel, fans have gotten creative with how they use it. The fruit’s sweetness and juiciness make it an ideal addition to everything from bright citrus salads to zesty cocktails and refreshing desserts. Its bold flavor also complements savory dishes—think citrus-glazed salmon or a tangy dressing for roasted vegetables.
All of that creativity may be a result of the fact that Sumo Citrus is here for a good time, but not a long time. Unlike standard grocery store oranges that are available year-round, Sumo Citrus has a limited growing season, running only from January to April. This short window has created an almost cult-like following, with fans stocking up as soon as they see the signature purple sticker in stores.
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I get it—now that I’ve experienced Sumo, I fully understand the impulse to grab them while they last. The anticipation is almost part of the appeal: Like cherry blossom season or holiday peppermint mochas, Sumo’s fleeting availability makes it even more special. And when the season ends? People (me) are already counting down the days until its return. Conclusion: Do yourself a favor and grab a few before they disappear for the year. Because once you’ve had a taste of this juicy citrus, there’s no going back.
Psst: Want a taste ASAP? The Sumo Tastemonial Tour is rolling into Belmont Park in San Diego from February 28 to March 1, Boreal Ski Resort in Tahoe from March 7 to 8, Craig Ranch Regional Park in Las Vegas from March 10 to 11, and La Encantada in Tuscon from March 14 to 15—or stop by House of Good in Venice Beach for the Ultimate Citrus Experience from February 21 to 23.
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