Right when you're getting used to a “no-carb” world, along comes a weight-loss trend even more difficult than forgoing bread: forgoing food.
Intermittent fasting (cycling between periods of fasting and eating) is the latest dieting craze to devour pop culture. The most buzzed about version is the “5:2” fast: Five days a week you eat like a normal human being, and the other two you, well, basically starve yourself. Talk-show host Jimmy Kimmel used the 5:2 to shed pounds, and a small army has joined him. To visit 5:2’s website is to visit some sort of online tent revival: “It’s very easy to do and to maintain!” gushes one dieter. Another enthuses, “It makes me feel healthy and energetic!”
According to science, it’s not bogus. In fact, fasting in short intervals allows you to “surprise” your body, which keeps your metabolism revved. There could be health benefits beyond just burning fat, too. A slew of studies have emerged suggesting that intermittent fasting, or “IF,” can trim cancer risks, lower cholesterol, improve insulin sensitivity, and even blunt the effects of aging. While there are obvious drawbacks (read: misery), the plan is also shockingly simple: On your two “fast” days, you eat 25% of your typical daily caloric intake—for me, roughly 600 calories. A slice of pizza, two Snickers bars, a giant platter of cabbage? All fair game. Sound crazy? It is. And it was, the 10 days I did it...
Jeff Wilser is the author of Alexander Hamilton’s Guide to Life, to be published by Three Rivers Press in September.
Day 1: Wednesday (Normal)
Mood: Here I go...
I visit the 5:2 website to calculate my BMR, or base metabolic rate. I input my height (6'1") and weight (173.5) and it spits out a BMR of 1,754 calories, meaning that’s how many calories my body burns even if I sit on the couch all day. Assuming a “moderate” activity level, the calculator gives me a target of 2,400 for eating “whatever I want.” That 2,400 is way more than I thought I’d have, so I celebrate with a sandwich for lunch and tacos for dinner.
But I know the next day, my first fasting day, will bring pain. My advice: Use nonfasting days as an opportunity to plan your fasting meals, since you’ll be at full strength. Once you’re fasting, it’ll be hard to concentrate.
Also know that there are multiple fasting strategies. Some people hoard their 600 calories for one big lunch, while some nibble throughout the day. I opt for a three-snack system: 200 calories in the morning, 200 at noon, and 200 for “dinner.” The logic? I’m a morning person and write immediately after breakfast, so eating nothing until lunch wouldn’t make sense. Think about when you need to be productive.
Morale: Cautiously optimistic.
Day 2: Thursday (Fasting)
Mood: Learning to eat invisible food
The morning feels surprisingly normal. I eat a small bowl of oatmeal (cinnamon but no syrup—200 calories), knowing that it will provide a mix of carbs, fiber, and protein. So far, so good. The diet has no restrictions on coffee, thank god, so I retain my will to live. Then the hunger hits. Best coping strategy? Drink lots and lots of water. Just pretend that it’s food. Mmmmmmhhhhh! Delicious. At noon I eat some Greek yogurt, as it’s low in calories (140) but packs plenty of protein. (Another good option would be a protein shake.) My gut rumbles. I get dizzy. In a work meeting, my stomach emits the sound of a dying aardvark. (I pretend it wasn’t me.) I fantasize about a hard-boiled egg I had planned as a snack, but the meeting runs long and the egg is abandoned. My soul is crushed.
On the subway home I try to focus on a book, but I’m so light-headed I read the same sentence 17 times. Finally I prepare my dinner: 260 calories left. I use an electronic scale to weigh precisely 80 calories of frozen grilled chicken (a much-needed jolt of protein), 40 calories of frozen spinach, and 110 calories of pasta, and I even have enough calories left over—30—to splurge on a quarter cup of marinara sauce. (The theory behind this meal? It feels “filling,” and it gives the illusion of a normal dinner, which can help psychologically. And psychology is half the battle with this diet.) This works: 260 on the nose. I wash it all down with diet ginger ale. Crunching the numbers, I feel like Matt Damon in The Martian, sciencing the shit out of my dinner.
Key lessons so far: Stock the fridge with what you’ll need in advance. You won’t have the energy for shopping; use a calorie-counting app (I recommend My Fitness Pal); and definitely splurge on a digital scale to track your progress. I’ve had good luck with the Fitbit Aria scale, which syncs with your step tracker. Forget about the gym on these two fast days. It’s just not going to happen.
Morale: Full-blown panic.
Day 3: Friday (Normal)
Mood: You mean hunger won’t kill me?
I wake up at 4 a.m. with hunger pangs. (Solution: Drink more water.) Today is supposed to be a happy day of normal eating, but the sleep deprivation dogs me all morning.
For some advice I chat with nutritionist Monica Reinagel, who surprisingly encourages the 5:2 fast. “In our current culture, we’ve gotten used to eating constantly. But the idea that you must eat every two or three hours is bullshit,” she tells me. “The minute we first feel the sensation of ‘my stomach isn’t full,’ we flip out. We think it’s the signal of impending organ collapse. I’m not advocating starving, but this mentality is partly psychological. You can develop a tolerance to those feelings.”
And what I found is, well, that’s actually true! Somewhat. Her advice was useful. In the past, I’d assumed that my hunger pangs mean that my blood sugar was crashing and that I was in imminent peril. Knowing that’s not really the case, I changed my mindset and just powered through it.
Morale: Somewhat calmer, but hopeful.
Day 4-5: Sat.- Sun. (Normal)
Mood: Yes, I’d love another beer, thanks!
I’m now 24 hours removed from the fasting, and I’ve practically forgotten about it, going about my life as usual.
Another beer! More chips! (I ate a diet of mostly salads, sandwiches, and, OK, maybe a burger. But I stayed (roughly) within the ballpark of 2,400 calories, give or take. I won’t pretend I felt any magical benefits, like being “more focused” or “sharper,” but I did feel like my normal self.
Morale: WTF, I’ve gained 2 pounds??
Day 6: Monday (Fasting)
Mood: Ah, the joy of a single olive
I quickly learn not to freak out about daily fluctuations in my weight but rather to zero in on the longer-term (i.e., weekly) trends. So I attack the day. Morning oatmeal: 200 calories. I feel sharp all morning. I heed the nutritionist’s advice: Mind over matter. When I feel hunger pangs, I don’t panic but just drink more water and try to focus. It helps. Greek yogurt at noon: 140 calories. I feel light on my feet. I power through the afternoon, a little light-headed and drooling at the idea of my 260-calorie dinner. I get home at 5:30 p.m., fighting hunger pangs but less panic, and bust out my scale, the pasta, and the chicken. Then my phone vibrates. “Calendar reminder. Drinks with Dolly.” Uh-oh. I had spaced and forgotten I was supposed to meet a friend for drinks. This gave me two options: 1) flake on the friend or 2) break the fast. I decided for secret option 3: I would have drinks with Dolly but somehow honor the fast. This would mean no chicken, no pasta, no spinach. If my fast were a video game, the difficulty level just went from beginner to advanced.
In the Uber to meet my friend, I googled “drinks with the lowest calories” and settled on vodka—125 a pop. I could drink two vodka-and-sodas and still have a cool 10 calories to spare.
“Have some olives!” Dolly says when I arrive, pushing me a bowl.
“Ah, I can’t.”
“Not one olive?”
I thought about it. Actually, I could have one olive. I had precisely enough calories left. I popped the olive in my mouth, swirling it, savoring it, sucking the pit. Another perk of the 5:2 diet? It takes a lot less alcohol to get buzzed.
Day 7: Tues. - Weds. (Normal)
Mood: Life in the fast lane is a little tricky
The fast can have sneaky benefits. It forces you to really think about how you consume food. My food tastes better. I appreciate it more. I’m feeling good and ask a friend if she wants to grab an impromptu dinner.
“Can’t. How about tomorrow?”
Tomorrow is a fast day. That won’t work.
“How about next Monday?” she asks.
Monday is a fast day. That won’t work, either.
“Let me know when you’re off your fast,” she says, trying not to laugh.
Day 9: Thursday (Fasting)
Mood: Dizzy with success
By now I’m a fasting pro. I make my oatmeal, I eat my yogurt, I power through the dizziness of the afternoon. My mindset has changed. I’ve learned that even if I’m hungry and I get a little dizzy, I can push through it and still function at, say, 65%. That’s not ideal, but it’s no reason to panic.
This gives me a strange renewed confidence. Certain my calendar is free, I make my tiny dinner of spinach, chicken, and pasta. All’s right with the world. I guzzle more diet ginger ale. This isn’t so bad. I brew some tea, smug in my mastery of the fast.
Day 10: Friday (Normal)
Mood: I lost 2.5 lbs and didn’t die
It’s surprisingly effective, and now I get the appeal. Even on the most painful starvation days, a cheat day is just around the corner. It can work. For two days a week, you can’t work out. You can’t (realistically) go on a date. And for two days, it’s difficult to concentrate and do your best work.
“Studies clearly show cognitive function is impaired when fasting,” says Liz Applegate, Ph.D., director of sports nutrition at UC Davis. “Math skills, reading, writing—they suffer. It’s no surprise you can’t focus. Your brain needs glucose for fuel, and you’re not supplying it.” From my experience, I’d agree with that.
Weight: 171 lbs (Total weight loss? 2.5 lbs)
Morale: Thrilled to hit the gym again.