I’d guess that most people reading this article want to get bigger, stronger, leaner, more athletic, or some combination of those traits. So what does fasting have to do with any of that? If you fast, you’ll crash your metabolism, lose all your muscle, and become weak and sickly, right? If done correctly, that couldn’t be further from the truth. Let’s take a closer look at some of the most common myths about fasting, the different forms of intermittent fasting, and the people who may benefit from it.
Fasting Myths
1. “Fasting will crash your metabolism” (also “Breakfast is the most important meal of the day”)
Everyone knows that skipping breakfast makes you fat. We’ve heard it forever from our friends, parents, and doctors. If missing just one meal is so disastrous, fasting must be at least dangerous and non-beneficial, right? Actually, the opposite is true. Studies show that your metabolic rate doesn’t drop until about 60 hours after your last meal. As a matter of fact, short-term fasting actually increases your metabolism due to the release of catecholemines like adrenaline and noadrenaline. So where did this myth come from? Studies correlate skipping breakfast with higher bodyweights. So does missing meals actually slow your metabolism and send you into “starvation mode?” Of course not. A more likely explanation is that people who are already overweight start skipping meals in an effort to cut calories, or people who don’t skip breakfast are more likely to engage in other habits they perceive as healthy, such as exercising and eating healthy foods. Equating correlation to causation is rarely fruitful. It’s like saying that most people who are in the NBA are tall, so if you are tall you’re in the NBA. Once you isolate all of the other variables involved, the hard data resoundingly debunks these myths.
2. Eating six meals per day is the best way to lose fat and maintain energy levels
Again, you’ve heard this myth from everyone around you for as long as you can remember, so it must be true. However, when you look back at the origin of this notion, it’s almost laughable. In the 1950s and 1960s, it became popular for competitive bodybuilders to eat six meals per day, but it wasn’t to lose weight. It was to gain weight! Imagine being 250 pound and trying to eat 5000 calories per day to put on muscle between competitions. Eating three meals per day of 1700 calories apiece is a daunting task, so they split it up into six smaller meals to cram all the food down their throats. Pretty soon, people started copying their eating patterns, seeing that they ate six meals per day and then showed up on stage shredded to the bone. The ironic thing is that most of those same bodybuilders would actually reduce the number of meals they ate as they were cutting for a show. Instead of eating more frequently, research shows that eating less frequently actually puts your body in the proper hormonal environment for losing fat. Keeping your insulin levels low is critical to shedding fat, and the longer you have between meals, the longer your insulin levels are low enough for effective fat burning.
But what about energy levels? Won’t you suffer from blood sugar crashes if you don’t eat every 2-3 hours? Again, nope! Your body is actually very efficient at maintaining energy levels. When blood sugar drops below a certain level your body releases glucagon, a hormone that signals for your body to utilize some of its glycogen reserves, keeping your blood sugar within a normal range. It takes 2-3 days to deplete your glycogen stores, and once there is no glycogen left, your body will convert fatty acids to ketones which your body can run on just as well. That’s right, your body has several weeks of stored energy, not several hours. There is actually scientific evidence that intermittent fasting will result in smaller blood sugar fluctuations than frequent feedings.
3. If I don’t eat frequently, I’ll get really hungry
This, too, is not the case. Well, I’ll backtrack for a moment. You will probably get hungry at first. You have a hormone called ghrelin that signals for you to be hungry. Ghrelin conforms to your eating schedule, basically serving as an internal alarm clock telling you when it’s time for you to eat, based off of your typical feeding pattern. As long as ghrelin is still telling you to eat breakfast, you’ll get hungry for breakfast. Once you skip breakfast for a week or two, your ghrelin cycle will figure things out and you’ll no longer be hungry at that time. As a matter of fact, skipping breakfast can actually decrease hunger at lunch time for fit people (or anyone with good insulin sensitivity). You can either believe me or read the next (admittedly boring) paragraph.
Although chronically elevated cortisol levels blunt insulin sensitivity, short-term spikes in cortisol actually improve insulin sensitivity quite dramatically. Your cortisol levels run in a daily pattern, peaking 30-45 minutes after you wake up (around when you’d be eating breakfast). When you eat breakfast, since cortisol is elevated drastically and insulin sensitivity is improved, your body can utilize whatever you eat much more quickly than it could at any other time of the day. Incidentally, this is probably the only shred of real science supporting the notion that breakfast is the most important meal of the day. However, for generally healthy people, this improved insulin sensitivity at breakfast isn’t necessarily a good thing. When you combine a cortisol spike with insulin sensitivity that is already great, you get a scenario where your body stores what you eat from breakfast so quickly that your blood sugar drops very quickly. Rate of change in blood sugar levels is one of the things that trigger a strong hunger response. For this reason, a fit person will end up much hungrier 2-3 hours after breakfast than they would have been if they didn’t eat it in the first place.
4. I will get small and weak.
Well, I’m glad I didn’t believe this one. Fasting improves insulin sensitivity. Insulin is responsible for bringing GLUT4 translocators to the surface of a muscle cell. The GLUT4 translocators bring glycogen into the cells, and glycogen supercompensation is one of the primary mechanisms that contribute to increased muscle protein synthesis (i.e. getting JACKED). In English: your body will probably be able to rebuild and grow your muscles more efficiently if you do some intermittent fasting. Also, your body’s rate of protein synthesis is not dependent on having constantly elevated amino acid levels, but on have pronounced spikes in amino acid levels. This means that NOT eating every few hours allows your amino levels to return to a baseline, allowing for a bigger spike when you eat and ultimately more protein synthesis.
As far as getting weak goes, being in a fasted state, as previously stated, increases catecholamine levels. One of those hormones, adrenaline, is primarily responsible for the “fight or flight” response. When you’re fasted, you not only produce more adrenaline, but you’re much more sensitive to it as well. That means you’ll be able to come much closer to the “grandma flipping a car off of her grandbaby” state. Oh, and as an added bonus, you’ll also be much more sensitive to stimulants such as caffeine.
Adrenaline + Caffeine + Improved Sensitivity to Aforementioned Molecules = Awesome
Types of Fasting
There are two primary types of mainstream intermittent fasting. One is the Leangains approach popularized by Martin Berkhan. In it, you have an 8 hour feeding window and a 16 hour fasting window each day. You’ll sleep through 8 hours of the fasting window, so it basically amounts to skipping breakfast, and eating your last meal of the day 8 hours after lunch. The other style is the Eat Stop Eat approach popularized by Brad Pilon. It basically revolves around eating normally for 5-6 days per week and fasting for 24 hours on the other day or two. A 24 hour fast isn’t as bad as it sounds. You eat dinner one night, skip breakfast and lunch the next day, and eat dinner the next night. I’ve tried both of these approaches and they both worked for me. Check them both out at http://www.eatstopeat.com/ and http://www.leangains.com/ if you’re interested.
Who is fasting appropriate for?
I’m not just an intermittent fasting fanboy. I tend to do it (usually Leangains style) because it works in my schedule. I’m a college kid and I like to sleep until about 8 minutes before class starts. If you just really love eating breakfast, it’s not going to make a tremendous difference whether you eat it or not. I just wanted to let you know that skipping breakfast (and perhaps even lunch) is an option that’s certainly on the table. If breakfast doesn’t fit well into your schedule, just skip it. If your primary goal is weight loss, you could probably benefit from intermittent fasting. You can still eat until you’re pretty full a few times a day and won’t have to feel like you’re grazing on pigeon-sized “meals.” If you’re an athlete with morning or early afternoon practices or games, you’d probably be better off eating prior so you’ll have a little more energy. If you’re trying to gain weight and already have issues eating enough in a day, by all means do NOT intermittent fast. Eat as much as you can as often as you can. That’s about it. After reading this article, don’t feel like you have to engage in intermittent fasting, but if you want to try it out you can now know that it’s a useful and scientifically validated tool.
Questions? Comments? Shoot them to gnuckols@harding.edu or find me on Facebook (Gregory Lee Nuckols)
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