I have experience with intermittent fasting for more than a year.
I don't eat breakfast each day and eat two meals, the first around 1pm and the second around 8pm. Afterwards, I fast for 16 hours until I begin eating again the next day at 1pm.
Interestingly, since I've began intermittent fasting I've boosted muscle mass (up 10 pounds from 205 to 215), lowered body fat (down 3% from 14% to 11%), boosted explosiveness (set a personal best with a clean and jerk of 253 pounds a few months back), and lowered the amount of time I've spent exercising (down from 7.5 hours per week to 2.5 hours per week).
In other words, I have become stronger, leaner, and more explosive even though I go to the gym less and eat less.
You might be thinking…
How can this be possible? Isn't skipping breakfast bad for you? Why would anyone fast for 16 hours daily? What are the advantages? Is there any science behind this or are you just mad? Is it dangerous?
Relax, friend. I've been known to do some weird things, but this is totally alright. It's simple to implement into your lifestyle and there are tons of health benefits. In this article, I'm going to break down intermittent fasting and everything that goes with it.
What is Intermittent Fasting and Why Would You Do It?
Intermittent fasting is not a diet, it's a pattern of eating. It's a way of scheduling your meals so that you get the most out of them. Intermittent fasting doesn’t change what you eat, it changes when you eat.
Why is it worthwhile to change when you’re eating?
Well, most importantly, it’s an amazing way to get lean without going on a weird diet or cutting your calories down to nothing. In fact, most of the time you'll try to keep your calories the same when you begin intermittent fasting. (Most people eat larger meals during a shorter time frame.) Additionally, intermittent fasting is a great way to keep muscle mass on when getting lean.
With all that mentioned, the main reason people do intermittent fasting is to lose weight. We'll talk about how intermittent fasting leads to fat loss in a moment.
Probably most essentially, intermittent fasting is one of the easiest techniques we have for taking bad weight off while keeping good weight on because it requires very little behavior change. This is a very good thing because it means intermittent fasting falls into the category of “simple enough that you'll actually do it, but meaningful enough that it will actually make a difference.”
How Does Intermittent Fasting Work?
To understand how intermittent fasting results in fat loss we first need to understand the difference between the fed state and the fasted state.
Your body is in the fed state when it is digesting and absorbing food. Usually, the fed state begins when you start eating and lasts for three to five hours as your body digests and absorbs the food you just ate. When you are in the fed state, it's very difficult for your body to burn fat because your insulin levels are high.
After that timespan, your body goes into what is known as the post–absorptive state, which is just a fancy way of saying that your body isn’t processing a meal. The post–absorptive state lasts until 8 to 12 hours after your last meal, which is when you enter the fasted state. It is much simpler for you body to burn fat in the fasted state because your insulin levels are low.
When you're in the fasted state your body can burn fat that has been inaccessible during the fed state.
Because we don't enter the fasted state until 12 hours after our last meal, it's seldom that our bodies are in this fat burning state. This is one of the reasons why many people who begin intermittent fasting will lose fat without changing what they eat, how much they eat, or how often they exercise. Fasting puts your body in a fat burning state that you rarely make it to during a normal eating schedule.
The Benefits of Intermittent Fasting
Fat loss is substantial, but it isn't the only benefit of fasting.
1. Intermittent fasting makes your day easier.
I'm big on behavior change, simplicity, and lowering stress. Intermittent fasting gives additional simplicity to my life that I really like. When I wake up, I don't worry about breakfast. I just grab a glass of water and begin my day.
I enjoy eating and I don't mind cooking, so eating three meals a day was never a hassle for me. Nevertheless, intermittent fasting allows me to eat one less meal, which also means planning one less meal, cooking one less meal, and stressing about one less meal. It makes life a bit simpler and I like that.
2. Intermittent fasting helps you live longer.
Scientists have long known that restricting calories is a way of lengthening life. From a logical standpoint, this makes sense. When you’re starving, your body finds ways to extend your life.
There’s just one problem: who wants to starve themselves in the name of living longer?
I don’t know about you, but I’m interested in enjoying a long life. Starving myself doesn’t sound that appetizing.
The good news is that intermittent fasting activates a lot of the same mechanisms for extending life as calorie restriction. In other words, you get the advantages of a longer life without the hassle of starving.
Way back in 1945 it was found that intermittent fasting extended life in mice. More recently, this research revealed that alternate day intermittent fasting led to longer lifespans.
3. Intermittent fasting may reduce the risk of cancer.
This one is up for debate because there haven’t been a lot of studies and experiments conducted on the relationship between cancer and fasting. Early reports, nevertheless, look positive.
This research of 10 cancer patients suggests that the side effects of chemotherapy might be diminished by fasting before treatment. This result is also backed by another study which used alternate day fasting with cancer patients and concluded that fasting before chemotherapy would lead to better cure rates and fewer deaths.
Finally, this comprehensive analysis of many studies on fasting and disease has concluded that fasting appears to not only lower the risk of cancer, but also cardiovascular disease.
4. Intermittent fasting is much easier than dieting.
The reason most diets fail isn’t because we turn to the wrong foods, it’s because we don’t really keep to the diet over the long term. It's not a nutrition issue, it's a behavior change issue.
This is where intermittent fasting shines because it's amazingly simple to implement once you get over the idea that you need to eat all the time. For instance, this research demonstrated that intermittent fasting was an effective technique for weight loss in obese adults and concluded that “subjects quickly adapt” to an intermittent fasting routine.
I like the quote below from Dr. Michael Eades, who has attempted intermittent fasting himself, on the difference between trying a diet and trying intermittent fasting.
Diets are easy in the contemplation, difficult in the execution. Intermittent fasting is just the opposite — it’s difficult in the contemplation but easy in the execution.
Most of us have contemplated going on a diet. When we find a diet that appeals to us, it seems as if it will be a breeze to do. But when we get into the nitty gritty of it, it becomes tough. For example, I stay on a low–carb diet almost all the time. But if I think about going on a low–fat diet, it looks easy. I think about bagels, whole wheat bread and jelly, mashed potatoes, corn, bananas by the dozen, etc. — all of which sound appealing. But were I to embark on such a low–fat diet I would soon tire of it and wish I could have meat and eggs. So a diet is easy in contemplation, but not so easy in the long–term execution.
Intermittent fasting is hard in the contemplation, of that there is no doubt. “You go without food for 24 hours?” people would ask, incredulously when we explained what we were doing. “I could never do that.” But once started, it’s a snap. No worries about what and where to eat for one or two out of the three meals per day. It’s a great liberation. Your food expenditures plummet. And you’re not particularly hungry. … Although it’s tough to overcome the idea of going without food, once you begin the regimen, nothing could be easier.
— Dr. Michael Eades
In my view, the simplicity of intermittent fasting is best reason to give it a shot. It brings a wide range of health benefits without requiring a complete lifestyle change.
Examples of Different Intermittent Fasting Schedules
If you’re thinking of giving fasting a try, there are several various options for working it into your lifestyle.
Daily Intermittent Fasting
Most of the time, I keep to the Leangains model of intermittent fasting, which uses a 16–hour fast followed by an 8–hour eating period. This model of daily intermittent fasting was popularized by Martin Berkhan.
It doesn't matter when you begin your 8–hour eating period. You can begin at 8am and finish at 4pm. Or you begin at 2pm and finish at 10pm. Do whatever is best for you. I tend to learn that eating around 1pm and 8pm works well because those times allow me to eat lunch and dinner with friends and family. Breakfast is usually a meal that I eat on my own, so skipping it isn't a big deal.
Because daily intermittent fasting is done daily it becomes very simple to get into the habit of eating on this schedule. Currently, you're perhaps eating around the same time every day without thinking about it. Well, with daily intermittent fasting it's the same thing, you just learn to not eat at particular times, which is so simple.
One possible drawback of this schedule is that because you usually cut out a meal or two out of your day, it becomes harder to get the same number of calories in during the week. In other words, it's hard to teach yourself to eat larger meals on a consistent basis. The outcome is that many people who try this style of intermittent fasting end up losing weight. That can be a good thing or a bad thing, depending on your goals.
This is perhaps a good time to mention that while I have practiced intermittent fasting consistently for the last year, I'm not fanatical about my diet. I work on building healthy habits that guide my behavior 90% of the time, so that I can do whatever I feel like during the other 10%. If I come over to your house to watch the football game and we order pizza at 11pm, guess what? I don't care that it's outside my feeding period, I'm eating it.
Weekly Intermittent Fasting
One of the best ways to get started with intermittent fasting is to do it once per week or once per month. The occasional fast has been demonstrated to result in many of the advantages of fasting we've already talked about, so even if you don't use it to cut down on calories consistently there are still many other health benefits of fasting.
Alternate Day Intermittent Fasting
Alternate day intermittent fasting includes longer fasting periods on alternating days throughout the week.
This style of intermittent fasting seems to be used often in research studies, but from what I have seen it isn't very widespread in the real world. I've never tried alternate day fasting myself and I don't plan to do so.
The advantage of alternate day intermittent fasting is that it gives you longer time in the fasted state than the Leangains style of fasting. Hypothetically, this would boost the benefits of fasting.
In practice, nevertheless, I would be worries about not eating enough. Based on my experience, teaching yourself to consistently eat more is one of the harder parts of intermittent fasting. You may be able to feast for a meal, but learning to do so every day of the week takes a little bit of planning, a lot of cooking, and consistent eating. The final outcome is that most people who try intermittent fasting end up losing some weight because the size of their meals remains similar even though a few meals are being cut out each week.
If you're looking to lose weight, this isn't an issue. And even if you're happy with your weight, this won't prove to be too much of a problem if you follow the daily fasting or weekly fasting schedules. However, if you're fasting for 24 hours per day on several days per week, then it's going to be very hard to eat enough of your feast days to make up for that.
As a result, I think it's a better idea to try daily intermittent fasting or a single 24–hour fast once per week or once per month.
Frequently Asked Questions, Concerns, and Complaints
I’m a woman. Should I do anything differently?
I haven’t worked with women on implementing an intermittent fasting schedule, so I can’t speak from experience on this one.
That mentioned, I have heard that women may find a wider window of eating to be more favorable when doing daily intermittent fasting. While men will usually fast for 16 hours and then eat for 8 hours, women may find better results by eating for 10 hours and fasting for 14 hours. The best advice I can give anyone, not just women, is to experiment and see what works best for you. Your body will give you signals. Follow what your body responds favorably to.
I could never skip breakfast. How do you do it?
I don’t. Breakfast foods are my favorite, so I just eat them at 1pm daily.
Also, if you eat a big dinner the night before, I think you’ll be surprised by how much energy you have in the morning. Most of the worries or concerns that people have about intermittent fasting are due to the fact that they have had it pounded into them by companies that they need to eat breakfast or they need to eat every three hours and so on. The science doesn’t support it and neither do my personal experiences.
I thought you were supposed to eat every 3 hours?
You might have heard people say that you should have six meals per day or eat every 3 hours or something like that.
Here's why this was a widespread idea for a short period of time:
Your body burns calories when it's processing food. So the thought behind the more meals strategy was that if you ate more often, you would also burn more calories throughout the day. Thus, eating more meals should help you lose weight.
Here's the problem:
The amount of calories you burn is proportional to the size of the meal your body is processing. So, digesting six smaller meals that add up to 2000 calories burns the same amount of energy as processing two large meals of 1000 calories each.
It doesn't matter if you get your calories in 10 meals or in 1 meal, you'll end up in the same place.
This is crazy. If I didn't eat for 24 hours, I'd die.
Honestly, I think the mental barrier is the largest thing that prevents people from fasting because it's really not that hard to do in practice.
Here are a few reasons why intermittent fasting isn't as crazy as you believe it is.
First, fasting has been practiced by various religious groups for centuries. Medical practitioners have also noted the health benefits of fasting for thousands of years. In other words, fasting isn't some new fad or crazy marketing ploy. It's been around for a long time and it actually works.
Second, fasting seems foreign to many of us just because nobody talks about it that much. The reason for this is that nobody stands to make much money by telling you to not eat their products, not take their supplements, or not buy their goods. In other words, fasting isn't a very marketable topic and so you're not exposed to advertising and marketing on it very often. The outcome is that it seems somewhat extreme or strange, even though it's really not.
Third, you've perhaps already fasted many times, even though you don't know it. Have you ever slept in late on the weekends and then had a late brunch? Some people do this every weekend. In cases like these, we often eat dinner the night before and then don't eat until 11am or noon or even later. There's your 16–hour fast and you didn't even notice it.
Finally, I would suggest doing one 24–hour fast even if you don't plan on doing intermittent fasting often. It's good to teach yourself that you'll survive just fine without food for a day. Plus, as I've outlined with multiple research studies throughout this article, there are a lot of health advantages of fasting.