I've been ignoring my mother for a week and a half.
For the past 10 days, I've stifled the small voice she instilled in the back of my mind to remind me that forgoing breakfast is nutritional doom — all for the sake of a diet known as intermittent fasting.
The diet essentially involves abstaining from food for a set period of time ranging from 16 hours to several days — and surprisingly, it has a lot of scientific backing.
Large studies have found intermittent fasting to be just as reliable for weight loss as traditional diets. And a few studies in animals have suggested it could have other benefits, such as reducing the risk for certain cancers and even prolonging life.
Silicon Valley loves it. A local group called WeFast meets weekly to collectively break their fasts with a hearty morning meal. The Facebook executive Dan Zigmond confines his eating to a narrow time slot; many other CEOs and tech pioneers are sworn "IF" devotees — some even fast for up to 36 hours at a time. I opted to try a form of the diet known as the 16:8, in which you fast for 16 hours and eat (or "feed," as some proponents call it) for eight hours. With this regimen, you can eat whatever you want — as long as it doesn't fall outside the designated eight-hour window.Here's how it went.
Most of Varady's IF research has involved obese people. Study subjects have lost a significant amount of weight — roughly the same amount they would have on a traditional diet that involves strict eating and calorie counting.
I told Varady I was trying out the diet not to lose weight but rather to find out how feasible the plan was. She said that while certain people shouldn't try intermittent fasting — those over 70, people with Type 1 diabetes, and women who are pregnant or lactating — "most people can give it a try."
Anecdotally, intermittent fasters report that their diets have helped them become more productive, build muscle faster, and sleep better. Members of a Silicon Valley startup called HVMN skip eating on Tuesdays and claim they get more work done on that day than any other. Varady said hundreds of people in her studies had reported similar benefits. "But we haven't studied or quantified any of that yet," she said.
I wanted the last meal before my first 16-hour fast to be good, so I made one of my favorites: homemade pizza with arugula and chicken breast.
Then I headed to a morning yoga class. I have to admit feeling a little trepidatious about exercising without my typical morning fuel.
The coffee helped curb the cravings for a while, but I started to feel ravenous at about 11 a.m. At 11:45, I set a timer on my phone for 15 minutes.
About 20 minutes into my walk, I began to feel slightly better, but I still couldn't really focus. When I got back to the office, I managed to get a few things done but still didn't feel like myself.
After lunch, I felt great. I was focused, full, and ready for an afternoon of work.
Luckily, the friends who invited me over wanted to eat at about 7, well within my "feeding window." We planned to order takeout, but, unfortunately, some of us arrived late. By the time we ordered, it was 8 p.m., and the food didn't arrive until 8:30 (after I was supposed to stop eating for the day). It felt weird to refrain from eating with everyone, so I decided that the next day I would break my fast an hour later to make up for it.
By 11:45 a.m., I was ravenous and shaking from all the coffee. I decided to eat at noon again despite the promise I'd made the night before. The rest of the day went all right, and for dinner I heated up a frozen meal.
In a rush, I grabbed a bar, a handful of almonds, and some seaweed snacks from my desk. I scarfed it all down as we drove.
Some of the intermittent fasters I spoke with told me they preferred to work out in the middle of their fast since exercising in that state gave them more energy during heavy bouts of training.
The science doesn't necessarily support this, however. In one large recent study, scientists reviewed several studies of Muslim athletes. They had been practicing one of the oldest forms of intermittent fasting — abstaining from food and drink from sunrise to sunset during the holy month of Ramadan.The reviewers found that as long as the athletes ate the same number of calories and nutrients when they broke their fasts, their athletic performance didn't suffer or improve during Ramadan.
I got two chicken tacos, chips and salsa, and a side of refried beans.
When I took a bite, the flavor of the grilled chicken seemed to dance on my taste buds. The corn tortillas were soft, light, and delicious. The beans were hearty and had a kick of spiciness that I loved.I realized I was tasting the food more intensely than usual — as if my senses were heightened. Perhaps narrowing my eating to a specific window of time made me pay more attention to my food. It seemed to make the act of eating more enjoyable, too.
There was fresh fruit, yogurt, and a plate of whole-grain muffins that looked as if they'd been baked that morning. I was tempted but moved on. Around 11, I was hungry and decided I'd earned a small cheat, so I added almond milk to my second cup of coffee. It tasted sweet, nutty, and wholesome — and after skipping out on pudding, I didn't feel guilty.
That turned out to be a good idea. My meetings ran well past noon, but I was able to break my fast with a hearty snack. When lunch arrived, I was still hungry and ate a blackened-salmon burger with salad and some berries. I felt as if I could have kept eating for hours but tried to control myself.
My lack of appetite is one of the reasons I think people would be drawn to intermittent fasting. Though the idea of a "fast" — which implies denying yourself food — sounds tough, I did occasionally experience less hunger overall when I did eat.
To celebrate the store's opening, there were plates stacked high with free alfajores — delicious South American cookies sandwiched together with a layer of dulce de leche. I quickly polished off four alfajores, which I later calculated had more calories than one of my normal meals — and way more sugar and refined carbs than I would normally eat in a day. But hey — I didn't break my diet!
By midnight, I'd eaten four biscuits and some vanilla ice cream, and felt as if I could keep going. Only my lack of supplies stopped me. I love sweets, but this was abnormal even for me. It was as if my stomach had no bottom. All I wanted was more chocolate.
Afterward, I felt much better than I had for the previous 24 hours. The problem with sweets (like the ones I'd gorged on) is that they're high in refined carbs and sugar, neither of which fill you up or fuel your body long term. My guess is that after I forgot to eat, my body went into starvation mode. Then, when I consumed heavy, rich treats, it went into overdrive and started craving more and more of them.
Varady told me that not drinking enough water was a central pitfall of the diet. "Many people who try the diet complain of things like headaches. But the problem is a lot of them aren't drinking enough water," she said. Roughly 20% of our daily fluid intake comes from food, so if you're fasting, you may need to add a few glasses of water to your day.
When I stick to a fairly healthy diet full of vegetables, whole grains, healthy fats (avocados and nuts), vegetables, and small amounts of lean meat and dairy, I feel good — no matter when I eat. And when I eat like that, I can enjoy the occasional sweet treat. But when I get too rigid with my eating by denying myself certain things, or when I forget to eat altogether, it puts me in a danger zone where I crave unhealthy foods that ultimately don't nourish my body.
Intermittent fasting also appeared to eliminate my late-night snacking habit and seemed to give me more energy throughout the day. I'm glad I gave it a shot, but for now, I'm back to three meals a day — plus the occasional sweet treat.