I Tried Intermittent Fasting for a Week (2024)

The night I realized I always need to carry snacks with me to stave off hangry spells, my sister was discussing the panel on sexual harassment and assault we'd just attended when I turned to her and said, "I'm sorry, I just can't with this conversation right now" in a voice that didn't sound sorry at all. She got this look on her face; the only way I know how to describe it is a "tuck your tail between your legs" look.

I'd seen it before. Whenever I'd go too long between meals, low blood sugar transformed me into a character much more frightening than the ones in those Snickers commercials. Some people can keep smiling as their stomachs grumble. I am not one of those people.

But I am a person who likes to try new things, especially when it comes to diet and exercise: Whole30, dry January, aerial yoga, trapeze, the list goes on. So when my editor asked me if I'd be game to try trendy intermittent fasting, or "IF," for one week, it was a quick yes.

Multiple Sclerosis runs in my family, and I'd read fasting can help quell some of the inflammatory symptoms. (I don't have it, but figured the info would be helpful). Plus, it's the diet that Jimmy Kimmel used to lose all that weight, and I too am always trying — okay, talking about trying — to drop 10 pounds. So, while I knew there was a decent chance that my husband would be on the receiving end of at least one hunger-induced meltdown, I decided to go all in.

Editor's note: Weight loss, health and body image are complex subjects — before deciding to go on this diet, we invite you gain a broader perspective by reading our exploration into the hazards of diet culture.

The Plan: Working Up to 18 Hours of Fasting

To get started, GH hooked me up with Jaclyn London, MS, RD, CDN, Nutrition Director at the Good Housekeeping Institute, to give me the low-down. She confirmed that while there are some claims that intermittent fasting can benefit your health and promote weight loss, the data pool is pretty small.

"My hesitation in recommending the diet overall is that research is pretty limited," London told me. "There have been some human studies linking IF to reduced cognitive decline in at-risk populations, improving markers of oxidative stress, and weight loss. But for the most part, larger-scale studies have found that there's virtually no difference between alternate-day fasting and simply restricting calories daily."

There are three main approaches to IF: time-restricted fasting, where you limit your eating to a set time every day and fast for the other 12 to 18 hours; modified fasting (a.k.a. the 5:2 diet that Kimmel follows), where you eat just 25% of your recommended daily calorie intake two days per week and eat normally otherwise; and alternate fasting, where you switch between periods of consuming zero-calorie foods and beverages and actually eating.

London recommended I go with the time-restricted fasting since you can start small and work your way up. Since the cognitive benefits are what I was most interested in, she encouraged me to focus on eating a Mediterranean-inspired diet full of nutrient-dense fruit, veggies, lean protein, whole grains, and healthy fats versus processed foods. "People follow all sorts of different eating styles on 'feast' days," she told me, "but Mediterranean-style eating plans have the largest body of evidence to suggest both weight loss or maintenance and cognitive benefits for the long term."

We decided I should start my fasting period at 15 hours, which meant on the first day I could eat between noon and 9 p.m but drink zero-calorie beverages at any point during the day. That didn't feel particularly restrictive, especially since I've never been a big breakfast person and typically only have coffee and a smoothie by noon. But what I learned is that food restriction is like going on a road trip: You don't think you need the bathroom, but the second you realize you won't have access to one for a while, you instantly have to pee.

Day 1: Starving by 8:30 A.M., Then Panic-Eating Lunch

That first day I woke up at 6:30 a.m. Two hours later, I was famished. My husband makes smoothies for us every morning (usually a combination of spinach, kale, frozen pineapple, banana, ground flax seeds, and this superfood green powder he gets at some healthy place) and I was basically drooling as I watched him down his before work.

Right away, I noticed I felt especially tired and unfocused. For one thing, it took me three hours to write something that normally would take one because my mind kept drifting off to what I was going to eat later. Also, my stomach was literally growling and I got a pretty annoying headache, something that happened again and again during those first couple days.

One thing that helped me get through the mornings was coffee. I usually drink two or three cups, with a little creamer. (I know, I know, almond milk is so much trendier/better for you, but it tastes like nutty water to me.) Since I was fasting, London advised I switch to half and half because it's harder to overdo. She also suggested not adding anything at all, but I just couldn't swing drinking it black.

When I was finally in the clear to eat, I threw open my cupboard and panic-ate two handfuls of granola just to get something in my system. I thought keeping my smoothie as my first meal would be no big deal given that "lunch" wouldn't be far behind. Big mistake. Huge. When you haven't eaten for 15 hours, an 8-ounce blend of kale and fruit just doesn't cut it. From that moment forward, I started planning a list of hearty "breakfast" options to replace it.

I decided to go a little café near my apartment for lunch and emailed London a couple items from the menu to get her opinion. She picked a bowl that had black and brown rice, tahini spread, roasted fennel, sweet potato, charred kale, pickled beet, a soft-boiled egg, and tamari dressing. I'd never had it, and it was super delicious and filling. In fact, I started to feel full about halfway through but, traumatized from how hungry I'd been that morning, I made myself finish the veggies to stave off any additional hunger pains. Afterward I felt like a new woman!

Unfortunately, that feeling didn't last. When I went to hot yoga that evening, it became clear that I was still very unfocused and low-energy. First, I lost the key to my locker and needed help looking for it. Then I forgot my coat not once, but twice. And I usually take every opportunity to flow through my vinyasa in class, but that day I found myself coming down from planks and spending more time in child's pose than I've ever done before.

I was wiped by the time dinner rolled around, so I went super on-the-nose and ordered Mediterranean food: grilled chicken, Greek salad, rice, hummus, and whole-wheat pita. It was delicious and I went to bed that night feeling full, but not overly stuffed the way I sometimes feel when I don't eat as healthfully.

Day 2: Less Hunger Pains, More Major Headaches

The next day was another 15-hour fasting day, but I woke up around 4:30 a.m. and couldn't fall back asleep, which made for verrrry long morning of not eating. The good news is I learned from my mistakes and had my leftovers from dinner first instead of the smoothie. That solved the problem of my growling stomach, but the headaches and spacey feeling were still there.

For dinner that night, my husband made homemade whole-wheat pizza with lots of veggies and a teeny amount of cheese. I also had a glass of red wine. All of it was London-approved. She said the trick to drinking wine while doing IF is to not overdo it, since having more than a glass or two could make me dehydrated and trigger feelings of hunger, not to mention lose the willpower to avoid late-night snacking. I made sure to finish the glass by 9 — so not a problem.

Day 3: Ordering Out — And Skipping the Burger

Heading into the weekend, I upped the fasting to 16 hours on Saturday and 17 hours on Sunday. I knew I'd eat at least a couple meals out, so London advised me to order entrees that were at least 50% vegetable-based with some lean protein, healthy grains, and fats thrown in to keep me full. This made the plan very easy and simple to adhere to.

On Saturday morning I made my own breakfast bowl with kale, cherry tomatoes, avocado, two eggs, and two slices of bacon. For dinner that night, my husband and I tried a new restaurant. Everyone around us got the burger, which is probably what I would have chosen had I not been doing this plan. Instead, I ordered an arugula, fennel, and tomato salad and my husband got the crab cake sliders. We also got a small plate of the lobster mac'n'cheese, and I used the "I'm on a Mediterranean diet" excuse to eat most of the lobster since London suggested I eat more seafood. (I don't like fish, so this seemed like a win-win to me.)

Day 4: Drinking More Water Like an IF Pro

On Sunday we brunched at a Mexican place, and I passed up what would have been my usual go-to (tacos!) in favor of a eggs benedict-like entree that came with salad and potatoes — the closest thing to a vegetable-based dish on the menu. Later, I snacked on green pepper slices dipped in hummus, and ate leftover veggie pizza and a kale side salad for dinner.

Even though the daily headaches were still persisting, I felt like I was finally getting the hang of things. I asked London about them, and she encouraged me to drink more water. "The point of this type of fast versus others is that you're not required to skip non-caloric beverages," she explained. "Drinking tons of water, seltzer, and unsweetened caffeinated beverages all 'count' toward your daily hydration needs."

Days 5-7: Hitting the 18-Hour Fasting Mark

Over the remaining days I increased the number of fasting hours to 18. It honestly didn't feel like a huge adjustment since I'd been working up to it, but it did mean I could only eat between 2 and 8 p.m., not a lot of time to fit in three meals. On most days my first meal was a kale salad with cherry tomatoes, avocado, and grilled chicken tossed in olive oil and lemon juice. I'd have my usual smoothie or an apple with peanut butter and granola a few hours later if I was hungry.

Then not long after that it would be time for dinner. One night I made zucchini noodles and broccoli tossed with pesto, topped with shrimp, and served with a side of sautéed chard. Another night I did grilled chicken with brown rice and veggies. One time I did go totally off the rails and order a chicken sandwich with fries. "Totally fine," London told me when I confessed what I'd done. "The point is that most of your choices are veggie-heavy, which makes the occasional indulgence all that much easier to have and appreciate. Plus, potatoes are a vegetable!" Best news ever!

The Results: Mostly Into the Mediterranean Diet

At the end of the week, I definitely felt lighter. When I weighed myself, however, the scale stayed exactly the same — down to the tenth of the pound. I also checked my measurements and apart from losing a quarter of an inch around my waist, there were no other differences in terms of my physical appearance.

I also didn't see any improvement in my cognitive abilities. By mid-week the fogginess and headaches had subsided, but who's to say whether it was better hydration, my body was acclimating to the plan, or a legit benefit of the fasting? I think I'd have to do IF for more than a week to get the answer to that question, and that's not something I'm particularly interested in doing.

London confirmed as much. "The 'brain fog' that comes with fasting is one of the main reasons why RDs like me aren't so quick to recommend it," she said. "You can't drive a car without gas, right? Having some food to fuel yourself properly for the day is 'feeding' your brain too. Since the cognitive benefits of fasting are mostly linked to long-term neurological benefits, not necessarily immediate ones, there's definitely an adjustment period."

The biggest personal benefit for me was sticking to a (mostly) Mediterranean-style of eating. Filling up half of my plate with veggies before anything else led to me making smarter food choices overall, especially when I ate out. And because I chose more nutrient-rich foods, I stayed fuller longer, making the mornings when I couldn't eat at least bearable.

If you're considering trying IF, London suggests starting small. "I'd encourage you to keep it as simple as possible," she said. "Experiment with an 'early bird special' for dinner, close your kitchen once you're finished, aim to get more sleep overnight, and sit down for a full breakfast at your usual time tomorrow."