Press Release:

SAN JUAN CAPISTRANO, Calif., April 29, 2019 /PRNewswire/ -- Got spring fever and want to shed those winter pounds? John Zehren's bestselling diet book Z-FAST: A Simple, Proven Method of Intermittent Fasting, is now available on Amazon audio, Audible and iTunes. In his book, Zehren reveals his fasting method as the secret to lasting weight loss.  Z-FAST has been featured on Just Jenny on Sirius XM and the Garry Meier Podcast.

Z-FAST: A Simple, Proven Method of Intermittent Fasting

Zehren discloses his secret of how to slam the door on calories and commit to a lifetime of intermittent fasting. Zehren found that the methods of Z-FASTallow him to maintain excellent health both physically and mentally.

Z-FAST is a practical approach to weight loss consisting of a simple formula where skipping meals several times per month helps dieters achieve life-changing results. There is substantial evidence of improved heart health for fasters. Fasting reduces the risk of weight gain and the potential to develop diabetes, while lowering blood insulin and blood pressure and increasing metabolism.

Portioning, long hourly workouts, calorie counting, special meals and weight loss fads don't work. Zehren offers compelling evidence for why these other methods fail.

Zehren's methods have allowed him to maintain his weight for eight years after a failed five-year weight battle with many fad diets. Zehren states, "Z-FAST was the only method that guaranteed initial weight loss for me and allowed me to keep it off for nearly a decade."

The author is pictured here with two of his daughters on his recent adventure hiking the Inca Trail to Machu Picchu.  He is feeling great despite hiking at the high altitude of the Andes Mountains while at a healthy weight maintained by Z-FAST!


Famous DJ Garry Meier Interviews Author John Zehren about Z-Fast

Listen to author John Zehren's interview  by choosing Episode 448 aired on February 18th. The interview starts at approximately 23:50 minutes into the show. This podcast episode is completely free of charge. Enjoy and join the Z-Fast Revolution! 

Z-FAST from the bestselling author John Zehren


Fasting for weight loss is the cure for the avalanche of bad yo-yo diets, fads, pills, programs, equipment, and machines that offer empty promises to life-long weight loss. Author John Zehren's new book, Z-FAST: A Simple, Proven Method of Intermittent Fasting describes his new program for periodically skipping meals to help dieters win the battle against weight gain. Portioning, long hourly workouts, calorie counting, special meal programs, and massive weight loss fads do not work.  Zehren offers compelling evidence why Z-Fast is truly revolutionary for life long weight loss when other methods fail.

“We are eating ourselves to death. The human body was not made for continuous feeding. The American way of cramming fridges with junk food and and continuously eating ridiculously high caloric foods is why the number one cause of death in America is heart disease,” Zehren says. “The costless cure for bad health is fasting.” The Z-FAST is a direct intervention and a costless cure for obesity. The National Institute of Health says that 2/3 of all weight loss experienced by dieters will be put back on within one year, and 1/3 of all dieters will weigh more than when they started. Mr. Zehren’s methods have allowed him to maintain his weight for eight years after a failed five-year weight battle with multiple fad diets. Zehren states, “The Z-FAST methodology was the only program that guaranteed initial weight loss for me and allowed me to keep it off for nearly a decade. Diets didn't work. On top of that: I had no time to exercise, no time to diet. I only had time not to eat.” 

Z-FAST is a practical approach to weight loss consisting of a simple formula where skipping meals several times per month helps dieters achieve life-changing results. Z-FAST chronicles the newly discovered health-boosting benefits of intermittent fasting. Stored fat is burned, and the reduced caloric intake results in weight loss while shrinking the stomach muscle. There is substantial evidence of improved heart health for fasters, and regular fasting and better heart health is linked to the way the body metabolizes cholesterol and sugar. Fasting reduces the risk of weight gain and the potential to develop diabetes (two known risk factors for heart disease), while lowering blood insulin and blood pressure and increasing metabolism. 





John graduated with a degree in Biology from the University of St. Thomas in St. Paul, MN. For more than 35 years, he has been employed in the medical and healthcare fields working to bring new cures, and FDA approved technologies to the market, specializing in the heart and brain.  Currently, John is the North American Vice President of Sales for the Neurovascular Division of a major American healthcare company.  

As a busy medical device executive who has a demanding career, John has discovered the secrets to what it takes to live a vibrant and full life. John has been happily married for over 26 years, has raised three daughters with his wife, and enjoys living in Southern California as an avid surfer. John is often described by those who know him best as an innovator, highly motivated, fun-spirited and someone who never takes “No” for an answer. 

After being asked about a million times how he manages to stay so fit, author John Zehren decided to share his passion for living life to the fullest and disclose a secret he has discovered. John found that using the methods of Z-FAST allows him to maintain excellent health both physically and mentally.

For more information, contact John at



After experiencing an over-40 creeping weight gain of 20+ pounds, John tried many different diets and eating plans and exercise regimens, and nothing worked. Balancing a family, career, and fun social events just didn’t allow time for extended periods of portioning, calorie or carb counting, or chasing down particular food products. John needed quick and easy relief and a way of eating that fit easily into his busy lifestyle. After vowing not to eat another bite of food until he was below 200 pounds, John happened upon the ease and guaranteed results of fasting. Using the methods described in this book, John easily lost those 20 pounds and can now testify to maintaining his ideal weight for over EIGHT YEARS STRAIGHT with zero yoyo diet maintenance.

John says, “I had NO time to exercise and NO time for diets. I only had time NOT to EAT. FASTING WORKS.” In Z-FAST, John shares the story of his successful fasting weight loss, the three personalized, proven methods for fasting, and the many health-boosting benefits that come with what has been discovered to be a natural way of eating. This book contains the answers for all those people who have asked over the years, “Hey Johnny Z, can you write that fasting thing down for me?”



 Weight Loss Advantages:

* Visible Immediate Weight Loss

* No Portioning Required

* No Dieting Every Day

* Burns Stored Belly Fat

* Shrinks Stomach

* Better Sleep on Fast Days

* Not Relying on Exercise

* No Counting or Measuring

* Eat Normal 90% of the Time

* Greater Concentration on Fasting Days 

* Win the Battle & Keep the Weight Off


Health Advantages:

* Weight Loss

* Burns Fat First

* Metabolic Rate Boost

* Human Grown Hormone Increases

* Physiological Power Over Constant Feeding

* Improve Insulin Levels

* Improve Heart Health

* Live Longer

The Reviews!


Dr. Mike, radiologist

I am a 44 yo physician/M.D. who let himself go a little too much since I turned 41 and had my first son. My story is nearly identical to the author’s in the sense that I am 5’10” tall and basically need to stay under 185 pounds to not look and feel overweight. 

I have done some crash course fasting/starving myself in the past to lose weight fast when i needed to (e.g. about two months before my wedding and, inadvertently, during residency). That was tough but my vanity got me through it. after the wedding i got up to 205 pounds a couple years later. i like to have a cocktail or two just like the author and enjoy life. 

The bottom line is another M.D. buddy of mine told me about the Z-Fast method. i got the digital version of the book and tried it out. what i love about the book is that it lays out a fairly simple method of when to fast. a template for success if you will. The author makes it idiot-proof. lays out your cheat sheet for fasting. 

Everybody is different but the bottom line is energy in versus energy out is what matters. you cannot deny the laws of thermodynamics. i’d much rather suck it up and eat very little a few days here and there and then allow myself on my “on days” to not worry about how much i consume. in the end my calories “in” are less than my calories “out” and keeping my physical activity constant (energy burned) i end up losing weight and easily keeping it off. 

I also believe, and it is backed up biochemically speaking in the book, that periodic fasting is good for the body. it promotes glycolysis in the liver and essentially causes the body to enagage in both catabolic (breaking down) and anabolic (later building up) activity within your body. i liken it to “keeping the pipes clean” similar to starting and driving and old car every week rather than letting it sit and rust and all the tubes erode and eventually break down. if you haven’t tried it you should. it is a small amount of pain and sacrifice to not eat as much as usual on designated days in order to enjoy the finer culinary delights the rest of the week. If you are not used to fasting, the first few times are difficult but you get used to it after that. my residency training was essentially an involuntary fasting primer so for me it was not a big deal.  

Again, the bottom line is the Z-Fast works and really is not difficult to implement into your daily routine. you feel great, lose weight, and keep your body running smoothly internally. If you’re reading this review it must have peaked your interest. Give it a try. You will not be disappointed. Good Luck!

Order Your Z-FAST Copy Now

Best Selling Author Chuck Bolton

…busy executives and professionals who have had marginal success with diets, while experiencing that middle-age weight creep. Johnny Z’s book is an informative and entertaining read, as he takes us through his own struggles with weight gain and diets and shares his approach for how he maintains his weight by intermittent fasting.

He presents three intermittent fasting methods that he calls Z-Fast. Johnny Z gave me a peek at his manuscript a few months ago and I read it in one sitting. Since then, I’ve put his advice into action, creating a new fasting routine, now doing one weekly 36-hour fast, supplemented by one weekly 24-hour fast, a few days later. I skip 5 meals a week this way and it’s not hard at all. The weight is coming off, but what I like best is the energy boost!

If you want to be healthier, more energetic and vibrant, buy and read Johnny Z’s book and do the Z-Fast intermittent fast he describes. I wish I had this book 10 years ago! Two thumbs for Johnny Z’s Z-Fast!

Jim, a personal trainer

Finally! A breath of clear and fresh air this book is to the weight loss struggles! I worked as a Personal Trainer/Sports Nutritionist for years. This book exposes the myth of eating 3, 5, and 6 meals a day that we have been brainwashed into believing! The Triple Burn effect the author describes in detail (exercising while on a fast) is spot on so true! This book tells it like no other I have read (and I have read countless on diet, food and exercise)! After reading the book I was motivated and inspired to try my fast. After 35 hours on fast, I had my best workout on the Concept 2 Rowing machine for a 10k! I felt great and reenergized I thank the author to opening my eyes to the world of Fasting, and the many benefits of Fasting periodically! A whole new world to the struggles of weight loss gas been simplified by this common sense approach! FINALLY !!!

Dr. Elizabeth, a cardiologist

For anyone interested in intermittent fasting, this book is a great introduction. It’s easy to read, engaging and practical - and provides a step-by-step plan for success. As a cardiologist, I see so many people struggle with weight loss and keeping weight off - and intermittent fasting can and does work. In addition, the emerging data about the health benefits of fasting above and beyond weight loss are fascinating and this book highlights some of that information. Not everyone is a candidate for intermittent fasting – and the book doesn’t address this in much detail. So that’s the only reason why I give the book 4 stars instead of 5.

Kevin M.

It’s been eight days, two fasting periods, and I’ve lost two and a half pounds using the Z-Fast method!

Just like Author John Zehren, my life is filled to the brim with career, family, and social commitments that make it exceedingly difficult to squeeze in complicated, time consuming diet programs that force me away from my favorite foods and make me feel as if I’m doing something wrong for hating them.

I’ve always despised trendy, attention grabbing self-help books. John Zehren’s straightforward guide to weight loss is stripped of complexities and gets right down to the central issue of losing weight: what to do, how to do it, and why it works. Like the title says, “Simple and Proven”.

John’s story is familiar. He loves life and food, he experienced weight gain and found a method based in fact and science to drop weight and become healthy again without obstacles or over-complications.

The method is as easy to follow as crossing days out on a weekly calendar. It includes practical advise and support for the psychological aspects of this simple life change from the author, and doctors, sports coaches, and business professionals who have used his method to success.

From the chapters and citations on the biological science supporting fasting, to interventions and responses to every weight gain situation, I felt like I was communicating with a good friend who discovered something amazing and wanted to share it.

I can’t wait to break my fast tomorrow afternoon, then enjoy a good meal on the way down to my target weight!

Mike J.

Great information, put together in a fun and "easy-read" type of format. The benefits from this book helped me lose 10 pounds. But more importantly than the weight loss, was the clarity of mind it gave me. I added a spiritual component to it, Which gave me another dimension of benefit. Thank you, John, for taking the time to put this all together. Extremely beneficial. I would recommend this for anyone that would like a no nonsense and easy to follow type of intermittent fast!

Learn more about Z-FAST from the author John Zehren

Websites To Check Out


The Calorie Calculator can be used to estimate the number of calories a person needs to consume each day. Specific to gender, height, weight & age.

My Fitness Pal

Calories burned from exercise. Specific to activity, weight and length of exercise.

Harvard Medical School -Calories burned in 30 minutes for people of three different weights

USDA Food Composition Databases

Database of approximately 231,000 different foods which lists their nutritional components.

Great article from Medical News Today  about the health benefits of intermittent fasting!

Fasting Success Stories

Dr. William F. Northrup III, MD 

Cardiac Surgeon, Corporate 

Edina, Minnesota

“Fasting makes more sense for weight loss than exercise. I use a full fast to maintain my life commitment weight.

I have been skipping breakfast and lunch for many years and believe in a full 24 hour FAST as a true FAST.

Walking a mile burns about 100 calories. It’s like spitting in the wind for weight loss and is an ineffective way to lose weight. I work out on a treadmill with an annual goal of 365 hours/year but not for weight management. FASTING and eating less is what works for weight management. I have been counseling people on this for years: push-offs instead of push-ups! "



Dave King 

Professional Sales Representative

Scottsdale, Arizona

"I have committed to a lifetime weight and use fasting to maintain it.   

The other significant advantage of fasting is that your stomach shrinks down big time.  So the next day or two you feel full on MUCH smaller meals. That’s really what I love about fasting … a physical change in my stomach OCCURS when NOTHING goes in it for 18–30 hours."


Mike Wilson 

Fitness Leader & Owner of Cape May Fitness & Sports  

Cape May, New Jersey

“We are seeing excellent results that can’t be obtained with exercise alone. Fasting has changed my clients’ lives and our professional approach to exercise program.” Mike states that he has experienced very little effect on his energy level when he is fasting and working out which includes Olympic weightlifting and powerlifting.

“On the heaviest of days I may choose not to fast, but other than that it’s exercise as normal. My rule of thumb is to break my fast after my work out. I fast 20 hours and then I work out. . . You get a longer boost of fat burn that way.”


Jon Ruby

Professional Driver 

Mission Viejo, California

”Calorie discipline was not in the cards because I eat whatever is in front of me.

Also, FASTING allows me to put time back on my schedule. Eating can use up a lot of time, especially when going out, so I save all that time and complete a project or work out (my favorite thing).

Calorie restriction was way too easy to cheat, and I always said that I would start “tomorrow.” But fasting works. I used it extensively as a secret to keep at a lean 185 pounds and easily maintain that weight.  I fast for an entire day, and by the end of the day, I always feel much better."

Dawn Cottrell

Cape May, New Jersey

Dawn began her weight loss journey in 2012 and joined Weight Watchers in which she would plateau after about 2 years. She joined Cape May Fitness & Sports to break this plateau through High Intense Interval Training better known as (HIIT). She successfully did so but just like anything else would soon plateau again. She quickly learned that in order to have sustainable weight loss through nutrition and exercise that the she needed to vary her training and also vary her nutrition plans. This is when she decided to try Intermittent Fasting. 

Dawn started off with a simple 3 times per week phase with 12 hours of fasting and 12 hours feeding. Dawn’s nutrition coach, Coach Wilson of Cape May Fitness & Sports out of Cape May, NJ would then continue to change her nutrition plan (IF) fasting and feeding times in phases of 30 days. Dawn’s success really started to pop when she arrived at the 3rd phase of the IF program when she was able to comfortably be able to withstand 5 days of IF which entailed 18 hours of fasting and only 6 hours of feeding time. 

Dawn is on her last phase of the program from Coach Wilson and then will begin the Z-fast method to sustain the hard months of summer. In the event Dawn is not at her goal weight, she will repeat from either Coach Wilson’s phase 2 or 3. At the moment she is to reach her goal weight, she will at that time implement the Z-fast method to maintain her goal weight. We have used the Z-fast in the past to sustain Dawn’s weight through vacations and/or holidays and worked to its entirety. When Dawn returned, we quickly started back on the same phase in which she had left on prior to her vacation or holiday break. Combining resistance training, HIIT, Coach Wilson’s IF phases along the Z-fast method. Dawn quickly transformed herself because IF was easy and fun to do after she broke through the first phase. 

Judy D.


Prescott, AZ

"I lost 2 pounds the very first week of doing Z-FAST! As a woman in my 70's, it is difficult to shed any unwanted pounds but this really worked!"

Steve B.

Furniture Store Entrepreneur

Orange County, CA

"I had a tropical vacation coming up with my family and wanted to be ready for the beach, hiking and water activities. I needed to drop a few pounds before going.  I decided to give Z-FAST a try  and lost 10 pounds over the course of a few weeks.  I did a couple full day fasts  each week to really lose the weight  a little faster because of the upcoming trip. I loved having my liquid reward at the end of each fasting day! Great tip Johnny Z."


"Hey John, I thoroughly enjoyed your book & I'm hoping this is the answer for me & yoyo dieting ! I've done it all, every diet out there.... Your book is so inspirational, I went on a fast the next day for 36 hours,felt pretty good, had a slight headache, no biggy, my only thing was I was so sleepy after the fast,I couldnt do anything but sleep, good thing I'm retired, I couldn’t have gone to work! I was wondering if that is typical of others too? I'm definitely going to follow your plan, I don't  want to waste the rest of my life worrying about food, your book made me see how much time is wasted thinking about what I can & can not eat! I feel empowered now, I can & will do this. I have about 50 lbs. to lose,I know it'll take some time but thats ok, I'll keep you posted....I have read other books on fasting over the years; none inspired me like yours; plain & simple, full of facts & I like your jokes too.... haha You're easy to relate to, keep up the great work & Thank You so much.... By the way I'm 67, soon to be 68 & finally I'm done worrying about food, better things to do with my time! You truly have inspired me!"


"I received your book yesterday and finished it today.  Great read and very interesting.  Even before receiving the book, I did my first full day fast (36 hours).  I think I did pretty well, but had really bad headaches the first night and all day yesterday.  I woke up with one today, but read something about it possibly being a lack of salt (I have hydrated well).  So, I took a pinch of salt on my fingertip and ate it.  I washed it down with my beloved coffee, of course.  The headache went away.  Yay!  After the second day, I am down 2.0 pounds.  Yes, I'm acutely aware of the decimal and I am very encouraged by this result . . . Thank you for a great book and I look forward to losing more weight and doing great things with my health through your Z-Fast!"


Amazon Bestseller!


Z-Fast T-Shirts are now Available!

Z-Fast t-shirts are now available for sale on Bonanza. Just click the red button to the right to be taken to Bonanza to order your t-shirt now! These stylish t-shirts are available in the following sizes: S, M. L & XL. They are 50% cotton and 50% polyester. These navy t-shirts are printed in yellow with gold piping at the neck and sleeves as shown in the picture above.  Wear your shirt proudly and let everyone know that you are part of the Z-Fast Revolution!

Pricing for all sizes is $25 + $5 for shipping.

Dawn Cottrell


Great job Dawn! You look amazing and must be feeling great.  Utilizing Z-FAST will help you maintain your healthy lifestyle choice for life! 

Stop dieting and start fasting!


A reader shares his lifetime commitment weight!


UPDATE: As of 10/1/18, Doug has lost 30 lbs since starting Z-FAST! 

Way to go Doug! 

We are proud of you!

Join The Z-FAST Revolution!


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