How to Fast for 40 Days: What I Learned From Decades of Extended Fasting
If you’re considering an extended fast — 10 days, 21 days, or even the full 40 — let me share what I wish someone had told me before I started.
I’ve fasted for decades. I began with one-day fasts and eventually completed a 40-day fast. Along the way I’ve helped thousands of Christians walk through extended fasts of their own.
Here’s what nobody warned me about: most of what’s written about Christian fasting was written by people who haven’t actually done it. Or who did one fast, decades ago, and built an entire ministry on that single experience.
I’m going to tell you what extended fasting is actually like. The parts the pretty books leave out. And what I wish someone had told me before I started.
How God Called Me to a 40-Day Fast
God impressed on me for several months that He wanted me to fast for forty days. But I wasn’t sure I could fast that long.
I had grieved over the moral condition of my country for at least thirty years, but this was a fresh and special working of the Holy Spirit. God was leading me into a depth of prayer far beyond anything I had ever experienced before.
I began my fast with a simple prayer:
“Lord, I will fast as long as you will enable me. I am looking to you to help me. I am claiming your promise: ‘Those who wait on the Lord shall renew their strength; they shall mount up with wings like eagles, they shall run and not be weary, they shall walk and not faint.'” (Isaiah 40:31)
God was faithful to His promise. My fast was the greatest forty days of my life spiritually.
But I had to learn — by going through it — that an extended fast doesn’t unfold the way most teachings suggest. It moves through distinct stages, and if you don’t know what’s coming, you’ll panic at exactly the wrong moments.
What I Wish Someone Had Told Me About the First Few Days
The first few days of an extended fast are not what most people expect.
You won’t actually be hungry — that’s a physiological impossibility this early. But your soul will throw a tantrum. Your mind will tell you you’re starving. Your emotions will insist you can’t do this. You’ll think you want a doughnut so badly you might die without one. None of it is true.
Then, just when you’ve gotten your soul under control, your body takes its turn.
You may experience weakness. Fatigue. Chills. Headaches. Nausea. Dizziness. Moodiness. You’ll wonder if you’re getting sick, if you’re harming yourself, if “fasting just isn’t for you.”
Here’s what most people don’t realize: the more severe these symptoms are, the more you need to fast.
It’s not spiritual — it’s physical. The most difficult job your body does is digestion. If you never give it a break, your body never gets a chance to do the deep purification it’s been waiting decades to do. The discomfort you feel during this window is your body finally taking the opportunity to cleanse itself.
This is the hardest part of fasting. And it’s the part where almost everyone quits.
They didn’t fail at fasting. They just experienced detox and mistook it for failure.
If you push through, something extraordinary happens. The hunger stops. The fog lifts. You feel a clarity you’d forgotten existed. The things of this world grow strangely dim.
You’re no longer fueling your body with food, so your body learns to fuel itself differently — and your spirit comes alive in a way it can’t when you’re constantly digesting.
But getting there requires understanding the pattern. Otherwise you quit three days before the breakthrough.
Why People Can Fast for 40 Days (And You Can Too)
People are often astonished when I tell them I’ve fasted for 10 days, 14 days, even 21 days routinely — and once for 40 days.
They say, “I could NEVER do that!”
My response is always the same: “That’s probably because you’ve only ever fasted 1-3 days, which is the hardest part. If every day was as challenging as those first few days, NO ONE could fast for very long.”
There’s a place you reach in an extended fast where food becomes a non-issue. Where you genuinely think to yourself, “Why did I ever care about food? I could fast forever. I should have been fasting all along.”
When you reach that point, you can continue fasting for days, even weeks. Not because you have superhuman willpower — but because the spiritual and physical mechanics have fundamentally shifted.
Most Christians will never experience this. Not because they couldn’t, but because they didn’t know it was on the other side of those first miserable days.
You don’t have to be one of them.
The Spiritual Discipline Most Christians Avoid
Down through the years, godly people who have done mighty things for God have testified to the necessity of prayer with fasting.
John Wesley, who shook the world for God during the Great Awakening, so strongly believed in the power of fasting that he urged early Methodists to fast every Wednesday and Friday. He refused to ordain anyone in Methodism unless they agreed to do it.
Martin Luther fasted. John Calvin fasted. John Knox fasted. Jonathan Edwards. Matthew Henry. Charles Finney. Andrew Murray. The list of Christian leaders who made prayer with fasting central to their lives is long — and the list of believers today who follow their example is short.
Why?
Because by medieval times, fasting as a discipline came to be frowned upon. For a thousand years, fasting has lain rusting and forgotten in a dark corner of the church.
But Jesus didn’t say if you fast. He said when you fast (Matthew 6:16).
For believers, the question isn’t should I fast? The question is will I fast?
What an Extended Fast Actually Does
The apostle James says:
“Come near to God and he will come near to you. Humble yourselves before the Lord, and he will lift you up.” (James 4:8,10)
Fasting prepares us for the deepest and richest spiritual communion possible. It clears our minds to understand what God is saying to us. It conditions our bodies to carry out His will.
When we persevere through the initial mental and physical discomforts, we experience a calming of the soul and a cooling of the appetites. We sense the presence of the Lord more than ever before. Fasting with a pure heart and motives brings personal revival and adds power to our prayers.
Through prayer with fasting we’ve seen:
- Increased effectiveness in intercessory prayer
- Deliverance from bondage
- Guidance in decisions
- Personal revival through the powerful moving of the Holy Spirit
- A deeper understanding of Scripture
- Prayer transformed into a richer, more personal experience
In Bill Bright’s own words about his 40-day fast: “My forty-day fast resulted in an even more exciting discovery of many golden nuggets of truth that I had not seen before. My prayer life continues to be more exciting. I find I can hardly wait to see how God is going to answer specific prayers.”
That has been my experience too.
Who Should NOT Fast
Let me be direct: not everyone should fast. Not because you’re “not spiritual enough” — that’s nonsense — but because fasting is a powerful physical and spiritual stressor, and some people genuinely shouldn’t put their bodies through it.
You should NOT fast (or should only fast under medical supervision) if you:
- Are pregnant or nursing
- Are physically emaciated or have a history of eating disorders
- Suffer from weakness or anemia
- Have tumors, bleeding ulcers, cancer, blood diseases, or have recently suffered a heart attack
- Have chronic problems with kidneys, liver, lungs, heart, or other important organs
- Take insulin for diabetes, or suffer from any blood sugar problem like hypoglycemia
- Are afraid of fasting because you don’t understand its benefits
If you have any underlying condition and you sense God calling you to fast, find a fasting-knowledgeable physician. Most regular doctors aren’t trained in therapeutic fasting and will discourage you out of ignorance.
What I Drink During an Extended Fast
I’ve used all of these. They all work. Here’s what I recommend, in order:
Bone broth (my current go-to) Beef, chicken, lamb, or a combination. Add Bragg’s apple cider vinegar or lemon to draw out the minerals from the bones. You can make it in big batches and store it in mason jars.
Pureed cabbage soup Start with bone broth, then add cabbage soup ingredients and whatever other vegetables you like. Puree it. Mason jars. Easy to have ready for the week.
Freshly juiced vegetables Probably the ideal — but time-consuming. You have to make it fresh every meal. Go easy on fruit juice; it spikes blood sugar.
The Master Cleanse Fresh lemon juice, Grade B maple syrup (Grade B matters — more minerals), water, and cayenne pepper. The classic.
My personal 40-day formula:
- 1 gallon of distilled water
- 1½ cups of fresh lemon juice
- ½ cup of pure maple syrup
- ¼ teaspoon of cayenne pepper
The lemon juice provides Vitamin C. The maple syrup provides energy. The cayenne pepper opens small blood vessels and helps the body cleanse itself of stored toxins.
Avoid: Coffee, tea, sodas. The caffeine, acids, and phosphorus are dangerous during a fast. When you feel hunger pains from caffeine withdrawal, just increase your liquid intake. Herb teas are permissible, but go easy on the honey.
Don’t drink milk. Milk is a pure food and therefore a violation of the fast.
Drink as much water as you like. Your body needs plenty of water — both to cleanse and to prevent dehydration. Keep a bottle nearby for frequent sipping. Water at “mealtime” fools the stomach into thinking it’s being fed.
How to Prepare for an Extended Fast
Most people get this wrong. They wake up one morning, decide to fast for 40 days, and start that afternoon. Then they wonder why they’re miserable.
Preparation is everything.
If you plan to go without food for several days, begin by eating smaller meals before you abstain altogether. This signals your mind that the fast has begun, and it “shrinks” your stomach and appetite.
Some health professionals suggest eating only raw foods for two days before starting a fast. This makes the transition far less drastic.
If you’re new to fasting, build up gradually. Start with one-day fasts. Then three days. Then a week. Build your spiritual muscle the same way you’d build physical muscle.
How to End an Extended Fast (Read This Twice)
How you break your fast is more important than how you start it.
I’m not exaggerating. People have done serious damage — sometimes fatal — by breaking long fasts incorrectly. After weeks without solid food, your stomach and intestinal tract have contracted. Suddenly reintroducing solid food can cause diarrhea, sickness, fainting, and in extreme cases, death due to shock.
Even a three-day fast requires care. Start with something thin and nourishing: vegetable broth, fresh watermelon, cantaloupe.
For my 40-day fast, I broke it with a cup of soup, followed by small amounts of watermelon and other fruits every few hours for a couple of days. That cup of soup was ecstasy. I had never tasted anything so vivid in my entire life.
Then several hours later, a small snack. Then another. The idea is to ease back into regular eating gradually over several days. Milk and meat are saved for last — they can cause adverse reactions if reintroduced too soon.
This requires discipline. But you’ll avoid the severe pain and potentially serious physical reactions that come from eating too much too soon.
The Spiritual Side Most People Don’t Expect
If you sincerely humble yourself before the Lord in repentance, intercession, and worship, and consistently meditate on His Word during your fast, you will experience a greater awareness of His presence. Your confidence and faith in God will be strengthened. You’ll feel mentally, spiritually, and physically refreshed.
My fast proved to be the greatest prolonged spiritual blessing of my life.
But I have to be honest with you about something else. Something nobody warned me about.
After an extended fast, there is an emotional process that catches almost everyone off guard. The enemy will use this exact window to try to convince you that nothing was accomplished, that you haven’t changed, that the whole fast was a waste.
That is a lie. But it’s a lie that catches most fasters by surprise, exactly because nobody talks about it.
I’ve come to understand that an extended fast actually moves through five distinct phases — not three or four — and the fifth one is the one that determines whether you protect your breakthrough or lose it in the first week after the fast ends.
The 5 Phases of Fasting
Through decades of fasting and walking thousands of Christians through extended fasts, I’ve identified a pattern that repeats every single time:
Each phase feels completely different. Each one requires a different response. And in at least two of the phases, your body or soul will actively lie to you — telling you to do exactly the opposite of what you should do.
If you don’t know which phase you’re in, you’ll quit when you should push through, or push through when you should stop. Both are dangerous.
I’ve put everything I’ve learned into a free guide called The Secret to Extended Fasts: Understanding the 5 Phases of Fasting.
Inside, you’ll discover:
- What’s actually happening in your body and soul during each of the 5 phases
- The two phases where your body and soul are actively lying to you (and what to do)
- The single litmus test that tells you you’ve entered the breakthrough zone
- The warning signs that mean it’s time to end your fast — even if you’d planned to keep going
- How to protect your breakthrough during the phase nobody else warns you about
It’s everything I wish I’d had before my first 40-day fast.
👉 Grab your free copy of The Secret to Extended Fasts →
Your Next Step
If you’ve read this far, something is stirring in you. Maybe you’ve felt the nudge for weeks, months, even years. Maybe you’ve tried to ignore it.
Don’t ignore it.
Extended fasting is one of the most powerful spiritual disciplines available to a believer — and one of the most ignored. Most Christians will never experience what’s available on the other side of those first miserable days.
You don’t have to be one of them.
If God is calling you to an extended fast, He’ll meet you there. But go prepared.
👉 Grab my free guide: The Secret to Extended Fasts
I’d be honored to walk this road with you.
Fasting in Church History
Down through the years, godly people who have done mighty things for God have testified to the necessity of prayer with fasting.
John Wesley, who shook the world for God during the Great Awakening that gave rise to the Methodist Church toward the end of the eighteenth century, is representative of such great spiritual leaders. He so strongly believed in the power of fasting and prayer that he urged early Methodists to fast every Wednesday and Friday. In fact, he refused to ordain anyone in Methodism unless they agreed to do it.
Other Great Christians Who Fasted
Other great Christian leaders who made prayer with fasting a part of their lives were:
- Martin Luther
- John Calvin
- John Knox
- Jonathan Edwards
- Matthew Henry
- Charles Finney
- Andrew Murray
- and many more
Fasting in the Bible
Fasting has always been a primary means of humbling ourselves before God both in the Old and the New Testaments (see Isaiah 58:5, Psalm 69:10, Matthew 23:12, I Peter 5:6, and James 4:8-10). Humility is an attitude of the heart. “A broken and a contrite heart, O God, you will not despise (Psalm 51:17) (KJV).” God will hear us and respond to our cry when we come before Him in humility and brokenness–acknowledging and repenting of our sins, and asking Him to cleanse us by the blood of Jesus and to fill us with His Holy Spirit.
Fasting is not always the easiest godly discipline to practice. For those unaccustomed to it, going without food can be a struggle. The mental and emotional battles that may break out when we fast can sometimes be unsettling. Veteran fasters say this is a sure sign of the need to abstain from food and draw close to God.
According to Paul:
— Galatians 5:17
“We naturally love to do evil things that are opposite from the things that the Holy Spirit tells us to do; and the good things we want to do when the Spirit has his way with us are just the opposite of our natural desires. These two forces within us are constantly fighting each other to win control over us, and our wishes are never free from their pressures (TLB).”
Jonah Fasted
When Jonah carried God’s warning of judgment to Nineveh, their king declared a fast (Jonah 3:8). Immediately, the people began to fast and mourn over their sins:
“When God saw what they did and how they turned from their evil ways, he had compassion on them and did not bring upon them the destruction he had threatened “
– Jonah 3:10
Fasting in the Time of King Johoshaphat
The power of fasting and prayer is seen again in the time of King Jehoshaphat.
Some men came and told Jehoshaphat, “A vast army is coming against you from Edom.” Alarmed, Jehoshaphat resolved to inquire of the Lord, and he proclaimed a fast for all Judah.
– 2 Chronicles 20
The people of Judah came together to seek help from the Lord (2 Chronicles 20:2-4).
Then the king stood in the assembly of the people at the temple and prayed to God: “We have no power to face this vast army that is attacking us. We do not know what to do, but our eyes are upon you.”
– 2 Chronicles 20:12
The Holy Spirit responded, speaking through the prophet Jahaziel:
“Do not be afraid or discouraged because of this vast army. For the battle is not yours, but God’s . . . Go out to face them tomorrow, and the Lord will be with you.”
– 2 Chronicles 20:15,17
The king and the people began to praise and worship the Lord and the next day they marched out with their singers in front praising the Lord. As they marched into battle, the Lord breathed confusion into the camps of the enemy, causing them to attack and destroy each other. Judah’s humility in fasting, prayer, and praise had moved the Lord to save His people from sure defeat.
40 Day Fast in the Bible
Throughout the Bible we have many examples of great releases and victories through fasting and prayer that changed the course of history:
- Moses twice fasted forty days (Deuteronomy 9:9,18) till his face shone with the glory of God.
- In the time of the judges (Judges 20:26)
- In the time of Samuel (1 Samuel 7:6), all Israel fasted.
- David fasted before he was crowned, when his child was ill, when his enemies were ill (Psalm 35:13), and because of the sins of his people (Psalm 69:9,10).
- Elijah, Ezra, Nehemiah, Esther, Daniel–all fasted in time of need.