Skip to main content

Ask Dr. Denton: It's Lent. Can You Explain the Effects of Fasting?

Fasting is Spring Cleaning for the whole person, body, soul and spirit

Fasting gives us, body and soul, a spring cleaning.  

Dr. Denton and Michelle Weiss in Paris-  where Dr. Weiss was lecturing.

Dr. Denton and Michelle Weiss in Paris- where Dr. Weiss was lecturing.

PORTSMOUTH, VA. (Catholic Online) - Dear Dr Denton: As the Lenten season unfolds, can you tell me the effects of fasting on my body?

Recently, I awakened to a new Lenten season. Lent is truly my favorite spiritual time of the year. For me, it is a time of great joy. It cleanses my mind, body, and most importantly my soul. I have spent the past year building up toxins from the world I live in. Largely, it is the result of my own choices. I came off the holiday season and …presto, I was not quite as spry as I was in October when I was enjoying those little red rubies we call apples.

While Lent can be viewed as a season of sacrifice and doing without, I believe that it is the season of rebuilding and laying down a foundation that will help to direct our spiritual well being and perhaps our overall health.

What do I mean? 

Prayer and fasting leads us to a deeper closeness to God and to peace and beauty within.  Interestingly, fasting also gives our body a time to clean out the weight of a heavy year. Fasting on a purely physical level does have some significant and wonderful benefits.

Let´s just start with calorie reduction. In the US, the American food factory produces enough food to fill every citizen with 3800 calories per day. By the way, we only need approximately 2000 calories per day to sustain a normal sized person.

So, how does fasting play a role in our health and wellness?

The most profound way is in the calorie restriction. Studies performed on animals and humans where caloric intake had been restricted have shown that it leads to increased longevity (a longer life). Please understand that I am NOT speaking of extreme fasting. The radical extreme fasts that are proclaimed to be the "cure all" for the body are far from the truth.

The problem is that caloric restriction data is often used as a means of promoting extreme diets and starvation type "de-toxing."  "You should be able to smell the toxins coming off your body," is the common type of language used to promote an extreme diet or what is called a detoxifying fast.

The truth is that in the extreme detoxification diets and low calorie fad diets the body does give off an odor that is often reported to be the "toxins" coming off.  In reality, when you drive your body into a starvation mode the body goes into ketosis. That is what has the somewhat sickly sweet smell. Not toxins, just ketosis.

In fasting, the body has a decreased calorie intake. The body needs those 2000 or so calories to stay at an even weight and function. When the calories are less than our daily needs we start breaking down our energy reserves…. fat and muscle. In a short term fast such as a day of bread, honey, and water the body burns those fat stores.

In a diet where carbohydrates are limited for days to weeks, or absolute calorie reduction in the 1000 range, the body responds by burning both fat and muscles stores. In absolute starvation when the fat is gone, the body burns muscle.

That is why we see the horrible pictures of children with large bellies and thin limbs. The muscles of the abdominal wall - as well as the muscles on the limbs - have been used for calories. Muscle is made up of protein. When the muscle breaks down it forms ketones as a waste byproduct.  In the ideal world, we fast enough to burn the excess fat stores. We also control our tendency to indulge our disordered appetites through focused prayer, meditation, exercise, and simple discipline.

How does fasting help the mind and body?
In the short term it is best understood through understanding the value of rest. The body needs rest to heal itself and to grow. During a day of fasting, the stomach and bowels are rested. The toxins that are produced by the body in the breakdown of food and the toxins in the food we eat are thereby limited. Remember those free radicals from my earlier articles? They are decreased because there are fewer being made as waste in your body. In addition, fewer are brought in with the foods we eat.

How does fasting help the brain?

Simply stated, the caloric rest has a mind clearing effect. As Americans, we often eat high carbohydrate, high calorie meals. Initially, with food intake, the brain gets a high calorie boost but as we begin to digest large amounts of food our blood flow is directed to the gut to help with nutrient breakdown and transport. Later, the insulin release is often higher than the caloric intake so the brain has a moment where the sugar in the blood is too low and we get tired and feel cloudy.

By fasting, the calories and carbohydrates we eat are limited. The body does not surge with too much insulin. Instead a small amount of calories are brought into the body so we can function and the remainder of our needs come from our own fat stores. The brain is rested because its needs are not in competition with the gut and the reduced insulin release allows the brain to get its supply of energy from balanced blood sugars.

A few simple recommendations:

Follow our Lenten calenda. Make Fridays, perhaps even Wednesday, your days to fast.

Start slowly - no meat. Then extend this to a low carbohydrate/ low fat day with water, a small piece of fish, honey on whole grain bread, a spinach salad with olive oil and a touch of vinegar.

Drink water over coffee, soda, or fruit drinks. If you need something else, or your caffeine headache is kicking in, the answer is tea. Try green tea as the primary choice followed by herbal teas or fruit teas such as lemon tea, hot apple spice or chamomile.

Remember prayer time in the morning to set the right priorities. Start the day right and you will finish right. A little walk in the evening or even midday will ward off those urges for sweets.

The truth is, fasting is extremely healthy for the body if the fast is not extreme. By that I mean not performed for days or weeks at a time.

But Dr D, there has to be more ………………

Yes, there is more.  The benefits of fasting are not just about the physical world, they are also about the spiritual world. Fasting is about becoming identified in solidarity with the poorest of the world in order to feel their hunger, their ache, their longing for sustenance. That is what compassion means. To enter into the suffering of another. It is for love -  and for the beauty and dignity of the human person. In our small sacrifice we become one with each other and then we truly are one with Christ, one with God.

May we all fast together and then share our gifts as one.

Dr Denton D. Weiss, M.D. is board certified in both Plastic and Reconstructive Surgery and Otolaryngology-Head and Neck Surgery. Dr. Weiss' approach to his medical practice flows from his convictions about the meaning of life which are deeply rooted in his Catholic Faith. He and his wife, Michelle strive for an integrated approach to life which recognizes the unity of the body, mind and soul. They call this approach "Bella Vitae" or "Beautiful Living". He, and Michelle, are contributing writers to Catholic Online.



Pope Francis: end world hunger through 'Prayer and Action'

Copywriter 2015 - Distributed by THE NEWS CONSORTIUM

Pope Francis Prayer Intentions for October 2015
That human trafficking, the modern form of slavery, may be eradicated.
Evangelization: That with a missionary spirit the Christian communities of Asia may announce the Gospel to those who are still awaiting it.

Keywords: Lent, Dr Denton Weiss, Fasting, Beautiful living,


E-mail:       Zip Code: (ex. 90001)
Today's Headlines

Sign up for a roundup of the day's top stories. 5 days / week. See Sample

Rate This Article

Very Helpful Somewhat Helpful Not Helpful at All

Yes, I am Interested No, I am not Interested

Rate Article

1 - 1 of 1 Comments

  1. Anthony Collins
    5 years ago

    Interesting article Doc. What would ideally be a one-day-a -week food and liquid diet to help a recovering alcoholic ( dry ) who finds it difficult to sleep and is trying to write a book and keep the brain focused? I am a devout Roman Catholic living by the sea in Devon, UK. I start my every day by thanking Our Lord for loving me and taking care of me. God bless and thank you again for your article. I go to every morning, even though it is mostly US orientated, to have a read and see look at the Saint of the day etc. God bless Anthony.

Leave a Comment

Comments submitted must be civil, remain on-topic and not violate any laws including copyright. We reserve the right to delete any comments which are abusive, inappropriate or not constructive to the discussion.

Though we invite robust discussion, we reserve the right to not publish any comment which denigrates the human person, undermines marriage and the family, or advocates for positions which openly oppose the teaching of the Catholic Church.

This is a supervised forum and the Editors of Catholic Online retain the right to direct it.

We also reserve the right to block any commenter for repeated violations. Your email address is required to post, but it will not be published on the site.

We ask that you NOT post your comment more than once. Catholic Online is growing and our ability to review all comments sometimes results in a delay in their publication.

Send me important information from Catholic Online and it's partners. See Sample

Post Comment

More Easter / Lent

'So it is written that the Christ would suffer and on the third day rise from the dead' - Luke 24:46

Ash Wednesday

Ash Wednesday marks the beginning of the Season of Lent. It is a season of penance, reflection, and fasting which prepares us for Christ's Resurrection on Easter Sunday, through which we attain redemption. continue reading

Palm Sunday

Palm Sunday, the Sunday before Easter, commemorates Jesus' triumphal entry into Jerusalem, an event mentioned in all four canonical Gospels. (Mark 11:1.11, Matthew 21:1.11, Luke 19:28.44, and John 12:12.19) ... continue reading

Holy Week

On Palm Sunday, we celebrate the first joy of the season, as we celebrate Our Lord's triumphant entrance into Jerusalem where he was welcomed by crowds worshiping him and laying down palm leaves before him. It also marks the beginning of Holy Week... continue reading

Holy Thursday

HOLY THURSDAY is the most complex and profound of all religious observances. It celebrates his last supper with the disciples, a celebration of Passover ... continue reading

Good Friday

On Good Friday, each member of the Church tries to understand at what cost Christ has won our redemption. In the solemn ceremonies of Holy Week we unite ourselves to our Savior, and we contemplate our own death to sin in the Death of our Lord ... continue reading

Easter Sunday

Easter is the principal feast of the ecclesiastical year. Leo I (Sermo xlvii in Exodum) calls it the greatest feast (festum festorum), and says that Christmas is celebrated only in preparation for Easter. It is the centre of the greater part of the ecclesiastical year ... continue reading

Fasting and Abstinence

For most people the easiest practice to consistently fulfill will be the traditional one, to abstain from meat on all Fridays of the year. During Lent abstinence from meat on Fridays is obligatory in the United States as elsewhere. Christ Himself said that His disciples would fast once He had departed (Lk. 5:35). continue reading

FAQs About Lent

Everything answered from when does lent end, ashes, giving something up, stations of the cross and blessed palms. The key to understanding the meaning of Lent is simple: Baptism... continue reading

Stations of the Cross

Stations of the Cross refers to the depiction of the final hours (or Passion) of Jesus, and the devotion commemorating the Passion. First Station: Jesus is condemned to death... pray the stations now

What did you give up for Lent?

What did you give up for Lent?

From the humorous to the bizarre, people have had interesting Lenten experiences. Tell us about what you are going to give up for this Lenten Year.
What others gave up »

Lent / Easter News

Good Friday

  • Good Friday

    On Good Friday, the entire Church fixes her gaze on the Cross at Calvary. Each member of the Church tries to understand at what cost Christ has won our redemption.

    The Cross

    In the symbol of the Cross we can see the magnitude of the human tragedy, the ravages of original sin, and the infinite love of God. Learn More

Ash Wednesday

  • Ash Wednesday

    Ash Wednesday marks the beginning of the Season of Lent. It is a season of penance, reflection, and fasting which prepares us for Christ's Resurrection on Easter Sunday, through which we attain redemption.

    The Ashes

    The ashes are made from the blessed palms used in the Palm Sunday celebration of the previous year. The ashes are christened with Holy Water and are scented by exposure to incense. Learn More

Stations of the Cross

  • Stations of the Cross

    Stations of the Cross refers to the depiction of the final hours (or Passion) of Jesus, and the devotion commemorating the Passion.

    Opening Prayer

    ACT OF CONTRITION. O my God, my Redeemer, behold me here at Thy feet. From the bottom of my heart... Pray the Stations

Fasting & Abstinence

  • 'Christ Himself said that His disciples would fast once He had departed' Lk. 5:35

    Abstinence. The law of abstinence requires a Catholic 14 years of age until death to abstain from eating meat on Fridays in honor of the Passion of Jesus on Good Friday. Salt and freshwater species of fish, amphibians, reptiles and shellfish are permitted.

    Fasting. The law of fasting requires a Catholic from the 18th Birthday (Canon 97) to the 59th Birthday (i.e. the beginning of the 60th year, a year which will be completed on the 60th birthday) to reduce the amount of food eaten from normal. The Church defines this as one meal a day, and two smaller meals which if added together would not exceed the main meal.
    Learn More »

Newsletter Sign Up

Daily Readings

Reading 1, Romans 10:9-18
that if you declare with your mouth that Jesus is Lord, and if ... Read More

Psalm, Psalms 19:2-3, 4-5
day discourses of it to day, night to night hands on the ... Read More

Gospel, Matthew 4:18-22
As he was walking by the Lake of Galilee he saw two brothers, ... Read More

Saint of the Day

November 30 Saint of the Day

St. Andrew
November 30: Andrew, like his brother Simon Peter, was a fisherman. He ... Read More