What is Intermittent Fasting?
Intermittent Fasting is a fairly new movement in the nutritional world. Pioneered by Lean Gains blog author Martin Berkhan and Eat Stop Eat author Brad Pilon, it has taken on near-mythical status among some followers for its results in weight loss and muscle building. I haven't read Eat Stop Eat because I'm not willing to pay $37 for a book, but the best primer I've found is the 3-part article by Max Shippee on Paleo Plan. I highly recommend this article -- it only takes ten minutes to read all three parts and Max does a great job illustrating IF for a normal person. If you have a bit more time and are interested in this subject, Dr. John Berardi's free e-book is a great resource.
There are several setups, including a full 24 hour fast occuring one or two days per week, a 16/8 split, i.e. an 8 hour eating window (Lean Gains), and a 20/4 split (the Warrior Diet). In my experiment, I attempted the 16/8 split.
Why Do Intermittent Fasting?
The main idea of IF is the reason paleo dieters are attracted to it: You can bet our ancestors didn't have three squares a day, and they certainly couldn't take Clif bars to snack on while out on the hunt. Research by Loren Cordain indicates most hunter-gatherer societies ate their only meal of the day in the evening. Some groups ate a breakfast consisting of the leftovers from the previous night's meal. That's all. Also, cavemen had to go for long periods of time without eating - sometimes days or more.
This anthropological evidence is hard to argue with, factually or intuitively. So, from an evolutionary perspective, do you really think that your metabolism goes into "starvation mode" after a few hours, burning away all your hard-earned muscle for fuel? Do you really think your body has adapted to immediately hoard away fat if you skip a single meal?
There is a growing body of evidence that disputes the conventional wisdom of eating small, frequent meals throughout the day in order to "stoke the metabolic fire." Mark Sisson's post on IF touches on the repair and restoration mechanisms on the human body during fasting, while Berkhan's post on the Top Ten Fasting Myths Debunked is a great consolidation of the latest studies. An excerpt from that post is below, explaining how the whole "breakfast is the most important meal of the day" thing may have come about:
"Breakfast skipping is associated with higher body weights in the population. The explanation is similar to that of lower meal frequencies and higher body weights. Breakfast skippers have dysregulated eating habits and show a higher disregard for health."
The final reason, and the one most important to me, is the one provided by Berkhan and supported by Tim Ferriss in The Four Hour Body. By fasting in the pre-workout period (although not necessarily working out while fasted) and making up for that calorie deficit in the post workout period, you're feeding your muscles at a time when they are most primed to receive the fuel, and at a time when fat cells have the least "appetite" for calories. This can lead to large strength and muscle mass increases, without a corresponding body fat gain.
That's basically it in a nutshell. I entered this experiment reluctantly; those who have seen me on Yom Kippur know that fasting can quickly turn me into a huge prick. But, as it turns out, I learned a lot and reaped significant benefits.
Highlights from my experiment
I did IF from May 8, 2012 until June 11, 2012. I fasted until around noon each day and usually devoured the majority of my day's calories after my workout. This post-workout meal always contained non-paleo starches (in the form of oatmeal in my case), since the objective was indeed to boost my blood sugar and insulin levels in order to replenish my hungry muscles. I kept it paleo for the rest of the day:
12 pm: Three hard boiled eggs over spinach tossed with salt, pepper, and olive oil
3 pm: Large kale and lettuce salad with lots of veggies, with a can of fish or rotisserie chicken. Apple, grapes, berries, nuts, etc for snacks.
Pre-Workout (Around 6 pm): Cyto-carb and whey protein isolate shake
Post-Workout: Double the amount of the shake, a banana, and an orange
Dinner (30 min after workout): Large meal (mostly paleo but sometimes with corn, rice), with a double serving of oatmeal and berries for dessert.
Keep in mind I was trying to gain overall poundage while minimizing fat gain. Each day, I got on the scale immediately after waking up. The morning is not the ideal time to measure muscle mass due to body water fluctuations, so I take the second chart with a grain of salt.
The main observations here are:
- My weight remained mostly constant. I did not achieve my goal of gaining weight, but I also did not lose muscle mass or gain extra fat. Remember that I was completely skipping breakfast and morning snacks, a very significant change, and there were no negative repercussions.
- In general, spikes in my weight corresponded with spikes in body fat percentage. The biggest spike was after a bachelor party in New Orleans. The following weekend, another spike, I had a family emergency and let's just say there was lots of chocolate and junk food involved.
- I actually LOST weight while I was out of town for 2 weeks, which was surprising. I did work out while out of town, but I also ate a good deal of non-paleo food, which usually causes weight gain. This could have been due to the fact that I went on two very hard and intense bike rides the last two days before I came home and weighed myself.
For my readers trying to LOSE weight, however, I think a Paleo diet with intermittent fasting could be an excellent regimen. Just remember not to "reward" yourself with lots of crappy food when ending your fast, and only eat larger meals immediately after workouts.
As far as how I felt, I was surprised by how easy it was to shift into an IF lifestyle. There were definitely a couple days when I bonked and just needed to eat before noon. But for the most part, my body settled into the rhythm nicely. The hardest part was the huge post-workout meal, which I sometimes struggled to finish.
Another interesting point is that I did not need any starchy carbs, like oatmeal or cereal, in the morning, the way I used to. As I wrote about in my breakfast post, I used to get light-headed in the morning if I didn't have some sort of starch. During IF, I could actually keep my diet completely paleo until the end of the day after my workout, when I would gorge myself on carbs.
TMI ALERT: On a related note, I literally stopped farting when I was on IF (until after dinner, that is). It was incredible. I was like a robot. I'm not sure what the mechanism is here, besides being completely paleo and nightshade-free all day until the evening. It could be a nutrient timing issue, too. Either way, I'll take it.
During IF, I did not feel the need to eat every couple hours, the way I always used to. I think this is due to a couple things:
First, IF could have "shocked" my body out of the hypoglycemia that is so typical in the Standard American Diet. When I did the 30 days of strict paleo, I needed a Lara Bar every couple hours just to keep my blood sugar up. Neely from Paleo Plan calls it the "hangries" and it takes a lot of time for this metabolic issue to heal. 5 months after starting Paleo, I still had some lingering hypoglycemia problems, and IF may have put the final nail in that coffin.
Second, IF taught me the difference between actual hunger and mental hunger / cravings. In the post I recommended above, Max Shippee makes some brilliant statements:
"If you’re willing to eat vegetables, you’re hungry. If not, you’re just craving...A heroin addict could make the argument that he’s just 'listening to his body' as he’s shooting up, and he’d be right. Know the difference between real hunger, and sugar cravings or even eating from boredom. If you’re not willing to eat vegetables, you’re not hungry – you’re just craving. Craving means addiction, and that’s not so good."
During my fasting period, especially in the morning, I dealt with cravings head on. I began to recognize what the feeling of actual hunger really is -- it's a more stable, clear, focused feeling that is not entirely negative, especially within the relatively short fasting period I was imposing on myself.
On a couple occasions, the old sugar and grain addictions reared their ugly heads and I got fuzzy, irritable and generally "hangry." When this happened, especially if I was at work, I shrugged my shoulders and cut my fast short, and sometimes had a muffin or two when it was really bad. No need to lose a morning's worth of productivity.
I didn't count my calories during this experiment, but I'm quite certain I was eating more during IF. And I still didn't gain any weight. So, after finishing the IF month, I thought to myself: "I'm getting on the bike more, yes, but I'm also making sure to lift weights at least twice a week. The laws of thermodynamics still apply to me, so with enough calories I should be able to gain some mass." So I kept the eating schedule from IF, but then ADDED breakfast back in, in the form of a big bowl of Kashi Autumn Wheat cereal with almond milk in the morning. And that was a disaster. As you can see in the chart, after just one week my body fat percentage shot up and my muscle mass percentage dropped to its lowest point since I began measuring. What's more, I felt queasy after breakfast and then felt crummy the rest of the day. This occurred each day, and it didn't get better over time.
Could the crummy feeling just be because I'm no longer used to grains? Well, no, because I've continued to eat a measured amount of grains after workouts. The post-workout grains do not make me feel great, but I think the problem is diminished since I'm eating lots of paleo stuff at the same time. Likewise, when I'm eating out and I have a piece of bread along with my otherwise paleo meal, I usually don't have significant issues. The crummy feeling and queasiness seem to be worst when grains make up the majority of calories in a given meal.
Could it be a placebo affect? Maybe, but I was really expecting to feel fine, and was looking forward to bringing back my cherished bowl of cereal in the morning. I certainly wasn't hoping to feel like crap to prove some point and say "Ha! Paleo is gospel! Pass the Kool-Aid!" As I mentioned in a previous post, I'm still not convinced grains are evil.
Could it be because of the gluten? Well yes, I actually think this could be the case. It could be that, after a half year of Paleo-ish eating with some IF thrown in for good measure, I'm over the hump on my grain addiction and I'm feeling the full benefits of a reduced-grain lifestyle. I'll be darned.
So, now what? I'm back to intermittent fasting, because I feel good when I do it. (I also can't think of anything else that's affordable to add into the breakfast slot instead of cereal, besides eggs. And, at three a day, I don't want to get sick of eggs.) However, I'm settling into a less intense 12/12 split, or sometimes 14/10 split. I'm doing this because A) I'm usually pretty darn hungry by 10 am, and B) I want more time to get my calories in, so I don't have to eat an uncomfortably-large binge meal at the end of the day.
And it's back to sweet potatoes. I've found that if I chop them up and put them in salads, I don't notice them as much and haven't gotten sick of them yet. Sweet potatoes will be essential as I continue to reduce my grain consumption.
Paleo and Cycling! Find out how to kick the goo habit, eat paleo and still excel in an endurance sport!
Paleo and Sustainability: This is the post I wanted to write when I first started the blog, and I have been procrastinating because it carries so much weight in my heart and mind. But I finally finished that dang Dragon Tattoo book and I checked out The Vegetarian Myth at the library today, so stay tuned!