This is the ninth piece in a series on how to develop a fasting lifestyle. Read the entire series here.

In week one of our plan, we dropped the carbs and upped the fats in our diet to switch our bodies from the ups-and-downs of sugar burning to slow-and-steady fat burning. In week two, you’ll break the habit of eating at fixed times throughout the day. Instead, you’ll restrict the window of time in which you eat. This will make your daily fast longer than it has been.

You Already Fast

Huh? Why did I write “longer than it has been”? Because you’ve fasted every day of your life. To fast is simply to abstain from food. When you’re sleeping, you’re not eating. So, if you eat your last meal at 7:00 pm, and don’t eat again until 7:00 am the next morning, you’ve survived a twelve hour fast. Good job! That’s why we call our first meal of the day “breakfast.” We’re breaking our nightly fast.

We don’t think much about this because we’re sleeping most of the time. Also, we don’t really enter a fasting state until several hours after our last meal. We should thank God that we need to sleep eight hours or so. Otherwise, few of us would ever really fast. And our bodies would be the worse for it.

As long as you’re running mainly on sugar, though, you need to eat early and often. That, in turn, keeps your blood sugar and insulin levels above the range needed for your body to really use its fat stores. And that, in turn, makes true fasting hard to do.

Once you’re running mainly on ketones and fatty acids rather than glucose, though, there’s no good reason to eat every few hours throughout the day. You can lengthen your usual nightly fast without your brain and body going into panic mode.

Delay Breakfast

You may be thinking, “Oh no. He’s going to say I should skip breakfast, isn’t he?” Well, that’s true, sort of. I understand the fear. I preached the gospel of oatmeal and egg white omelets for years. Skipping it, I thought, would slow down my metabolism and cost me lean muscle. But as I noted in an earlier piece, that idea is wrong. When your body first moves into a fasted state, it kicks up its metabolism and boosts growth hormone. That gives you energy, and helps your body save muscle and burn fat.

There’s no biological need to eat right after you get up in the morning. Nor do you need to eat in the morning at all. This is a custom, not a necessity.

Besides, strictly speaking, your first meal of the day will be breakfast — it will break your fast — no matter when you eat it. So, think of this part of our plan as delaying breakfast. It’s called time-restricted eating. It has lots of health benefits. For instance, if you’re sticking with the food plan from week one, these time limits will lower your fasting blood sugar and make you more insulin-sensitive. These perks will help you adapt to a fasting lifestyle.

The Sixteen-Hour Fast

I presume you already fast for about eight hours at night and eat over a sixteen-hour period during the day. If so, then for the next few days, just flip that. Pick an eight-hour window in which you eat as much as you did last week (with the same balance of carbs, fat, and protein). For the other sixteen hours, fast from all food. Drink lots of water throughout the day, and sip warm bouillon if you like. You’ll need the salt. Just make sure it has very few calories. And check for weird additives.

Of course, unless you’ve done this before, your body will expect food at fixed times. Your stomach will growl around lunch and dinner time just as surely as Pavlov’s dog salivated when he heard the bell ring. You’ll have to resist little body signals, such as a gurgling stomach.

But if you’ve followed the rules from week one, you won’t feel desperate for food.

The easiest way to do a sixteen-hour fast is to wait for your first meal of the day. Eat breakfast at 1:00 pm. Then stop eating at 9:00 pm. Or start at noon and end at 8:00 pm. Whatever works best for you.

20 Hours

Once you find that this is not as hard as you thought it would be, extend the fast to twenty hours. In other words, eat all your meals during a four-hour time window. You can try different times or pick the slot that works best for you. 6:00 pm to 10:00 pm works best for me. But some people like to start earlier in the day.

You don’t need to restrict calories. In theory, you can eat as much as you were eating before. But in practice, you’ll probably eat less. It’s hard to pack three full meals into four hours when you’re eating lots of fat and very few carbs except for green veggies. Don’t force yourself to eat more once you feel full.

Again, don’t forget to drink lots of water and perhaps salty bouillon. If you like coffee or tea, that’s fine too. Just don’t add calories to them during the fasting window.

What Do I Do with the Extra Time? Pray!

You’ll now be doing a real daily fast, even if you’re netting the same amount of food per day. You’ll also have extra time in your day, because you’ll spend less time eating. What should you do? Isn’t it obvious? You should pray. That includes mental prayer, memorized prayers, and written prayers; prayers alone and prayers with your family; praying the divine office; spiritual reading; reading and studying Scripture.

If you’re Catholic, you can attend daily Mass or Eucharistic adoration. Protestants can seek out other daily worship services.

Remember, our goal is to adapt to a fasting lifestyle. This includes regular fasting and prayer.

It also includes feasts, which I haven’t said much about. I’ll do that next.

Jay Richards is the Executive Editor of The Stream and an Assistant Research Professor in the Busch School of Business and Economics at the Catholic University of America. Follow him on Twitter.