The Fasting Reset: Real People, Real Results, Real Renewal

How Strategic Fasting Triggers Healing, Reverses Disease, and Restores Energy at Any Age.

One of my colleagues, a surgeon who runs marathons, pulled me aside to ask about fasting. He said that another physician who is into health and longevity told him that a 72-hour fast was the best way to stay young. He wanted my opinion because he was a little incredulous since doctors are taught that fasting is bad for health.

It just so happened that the day before speaking with the surgeon, I received the following message from a patient:

My 30 Day Fasting Miracle 

General overview of my 30 x 30 fasting miracle. Only drinking water + no eating

In 30 days, I lost 30 lbs, Started at 5’6” 180 Lbs. ended 30 days later 150 Lbs.

I Regained more brain-cognitive function + more energy, felt more alive than I have felt for the last few years.

Overall in general – on the plus side: I have more physical energy, increased life force, and motivation to do things, More mental clarity + sharpness, I have been 2-3 hrs a day more active, more involved with life, doing a lot of activities. + I felt so much more happy, joyful + alive with more mental and inspirational clarity.

I am, at the same time, dealing with another patient who was having issues. Jerome was a man in his 80s who was having a lot of problems with his mind and his body. “My brain just won’t work right!” he complained. I asked about exercise, but he had arthritis in both knees and couldn’t even take the dog for a walk. “They shoot horses, don’t they?” he asked. He was an extremely tough nut to crack because he was not able to change his diet. His wife made the food, and he had no control over what she made. Moreover, she was a good cook, and he said he wasn’t going to let any of it go to waste. That’s how he got into this mess.

“Well, I guess your only option is to fast until you reach your ideal body weight.” He was more than 100 pounds overweight, so that could take a long time. “That’s CRAZY!” he gasped. “Can anyone actually do that?” So, I told him a story:

The Remarkable Year-Long Fast of Angus Barbieri

In 1965, Angus Barbieri, a 27-year-old Scottish man from Tayport, Fife, embarked on a remarkable 382-day fast to lose weight.[1] Weighing 456 pounds at the start, Barbieri initially planned a short fast to get started. However, he began to feel better after losing some weight and decided to continue fasting until he reached his goal weight of 180 pounds.

During the fast, from June 14, 1965, to June 30, 1966, Barbieri consumed no solid food, subsisting on zero-calorie beverages like black tea, coffee, and sparkling water, along with vitamins, electrolytes, and yeast for essential nutrients. In the final weeks, he occasionally added small amounts of milk or sugar to his drinks. He lived at home, frequently visiting his doctor for checkups, including blood and urine tests, which showed consistently low blood glucose levels (around 30 mg/dl) but no adverse effects. His body relied on extensive fat reserves for energy, and he reportedly went 37–48 days between bowel movements due to minimal intake.

Barbieri lost 276 pounds, reaching 180 pounds, and broke his fast with a boiled egg, bread, and butter, stating, “It went down OK. I feel a bit full, but I thoroughly enjoyed it.” His feat was recognized in the 1971 Guinness Book of Records as the longest recorded fast.

One essential note is that seven years later doctors at the University of Dundee found no ill effects from the fast, and Barbieri maintained a weight of 196 pounds. He did not gain back the weight, as dieters often do, since fasting resets the “fat thermostat.”

I explained to Jerome that if Mr. Barbieri could fast for over a year, he could fast for a few weeks. He was interested, but we had to get his wife on board. I asked him to bring her to his next appointment, and we would discuss it with her. When she came in, I explained how fasting initiates the anabolic metabolism, where the body repairs everything on a cellular level. I described the work of Upton Sinclair, a Pulitzer-Prize-winning author who discussed fasting as a cure for many illnesses.

Sinclair suffered from chronic ailments throughout his early life, including digestive issues like dyspepsia, stomach troubles, and neurasthenia (a term used at the time for nervous exhaustion). Frustrated by conventional medical treatments, he began experimenting with alternative health practices in the early 1900s. Sinclair wrote a book in 1910, The Fasting Cure,[2] which chronicled his own fasts and those of others who were cured by fasting. He claimed to have undertaken several extended fasts, including two of approximately 10–12 days each, followed by shorter fasts of two to three days. He reported that these fasts “completely made over” his health, alleviating his digestive issues, boosting energy, and enhancing mental clarity. He described fasting as a way to “reset” the body, allowing it to heal by resting the digestive system and eliminating toxins. He continued to fast occasionally throughout his life and lived to age 90.

Fasting: A Natural Reset for the Body and Mind

This “reset” is exactly what Jerome needed. However, his wife was not happy about her husband not eating her food. She wanted to cook for him, because food represented love to her. I explained that he had stored a lot of energy on his body for a long time, and it was creating many problems, such as inflammation, heart disease, sleep apnea, and arthritis. He would likely live longer and be more functional if we took a short vacation from food. He would be able to use the fat he had been saving all these years. I told her the story of someone I knew named John.

John came into the office in some distress. He was sweating just from walking to the office from his car, and it wasn’t hot. He said he had chest pain from severe heart disease and was told by his cardiologist that if he didn’t have a bypass surgery, he wouldn’t survive a month. “I don’t want that surgery, doc, I know that it causes brain damage!” I asked him what he planned to do, and he asked if I would help him fast until he got better. I had already read The Fasting Cure so I was ready to help him. He drank only water for thirty days, and at the end was able to play a full game of basketball with no chest pain. Three years later I saw him, and he continued to exercise pain-free.

Jerome’s wife agreed to a trial period of a week to see what happened, so he started his fast. We had to keep a close watch on him, so he sent me his numbers every day: weight, blood pressure, heart rate, oxygen level, blood glucose, and ketones. The first few days were hard, as he was getting low blood glucose levels several times a day. The episodes only lasted a few minutes, so we did nothing. He pushed through, and after about five days he was feeling better. He had more clarity of mind and wanted to continue. His wife agreed.

At day 17 there was a celebration in the family and he was given food to eat. Sometimes breaking a fast is unexpected, and he ate. He came in to see me after that and was so surprised that he felt normal. He could walk the dog a mile without any knee pain, he felt very clear-headed. He felt so good, but had lost only twenty pounds, so he wanted to continue.

We discussed a healthy way to fast, including water with electrolytes: 1/8 teaspoon of salt in a cup of water. 2-4 cups per day. He could also break up the fast into shorter segments, just fasting for a few days per month on a regular basis. Now that he could walk, exercise would help as well.

Jerome has continued to improve, although more gradually. There is no rush. This is a process, not an event. His medical options were limited, as I have seen many others with these problems gradually decline, becoming less and less functional. Fasting turned him around from gradual decline to gradual improvement. Medications cannot offer that.

After describing these things to the surgeon, he said he was going to do more research. I directed him to Dr. Valter Longo from USC,[3] and Dr. Dale Bredesen from UCLA,[4] who have done a great deal of research on the subject.

 

Fasting FAQ: Autophagy and Beyond

What is AUTOPHAGY?[5]
A: When you don’t eat, your body uses the excess nutrients that are already stored in the body, recycling damaged or unnecessary components, such as proteins, organelles, and pathogens. The benefits of autophagy are wide-ranging and critical for health, particularly in the context of aging, disease prevention, and metabolic balance. It removes dead, dying, and infected cells. It eats cancer cells. It uses up amyloid plaques and misfolded proteins. It cleans out all the cholesterol in arteries. It also helps build mitochondria for energy production.

How do I get autophagy?
A: Fasting for about 48 hours induces autophagy. Exercise during fasting improves the effect. A 3-5 day fast is optimal for thorough cleansing.

General Timeline for Autophagy During Fasting

• 12–16 Hours: Minimal Autophagy
• 16–24 Hours: Moderate Autophagy
• 24–48 Hours: Robust Autophagy

Beyond 48 Hours: Sustained/Deep Autophagy: Prolonged fasting (3-5 days) maintains high autophagy levels, with potential for deeper cellular repair and stress adaptation.

Is it safe to fast?
A: We have a way to store food during times of plenty so that we can remain healthy when there is a lack of food available. Lean times are a natural and normal cycle of life. People have fasted (or starved) safely for millennia.

Do I need medical supervision?
A: For thousands of years people have fasted without medical oversight. Mr. Barbieri went to a doctor regularly and did testing, and even though he had low blood glucose levels, he continued to do well and had no ill effects. He never needed any treatment while fasting for over a year.

How much water can I drink?
A: Drink when you’re thirsty. It’s not healthy to push too much water as it can lower the electrolytes. I often recommend a pinch of salt in your water to maintain electrolyte balance.

Can I have smoothies, juice, broth, or other liquids?
A: Everything you put in your mouth breaks the fast, because the stomach stops making GHRELIN when anything is in it – even water. However, the stomach empties according to calories so plain water will empty quickly and not disrupt the fast very much. Tea and coffee are like water, except that they can cause dehydration because of caffeine. Other drinks, especially anything with flavor, should be avoided.

What about a “dry fast?”[6]
A: Research indicates that fasting without food or water may be even better than drinking water. When nothing enters the stomach, there is an uninterrupted supply of GHRELIN, which induces autophagy and the anabolic metabolism (cleanse, detox, rebuild, repair). However, this is something that must be practiced gradually. Start with one day for a few times, then go to two, then to three. I wouldn’t recommend more than three days in a row.

How many days can I fast? [7]
A: There is no limit, but it is wise to stay near your ideal body weight. You will burn about one pound of fat per day while fasting. That means if you are twenty pounds overweight, you should not fast more than twenty days. The other way is to have a goal, like Mr. Barbieri, and don’t eat until you are at that weight. Anyone who is at, or below, their ideal body weight should probably not fast more than three days.

Can I split a long fast into a few short fasts?
A: In fact, it may be best to break up weight loss fasting. For example, if you need to lose twenty pounds, you can do a four-day fast five separate times.

Should women fast?[8]
A: Women can fast, and have the same benefits as men, but there are some caveats to consider. Women with a menstrual cycle would do better to fast in the first 14 days of their cycle (the first day is the first day of bleeding). They also should not be doing long fasts during pregnancy or when breast-feeding.

What do I eat to end a fast?
A: It seems the best way to begin eating after a few days or more of not having anything is to start with fiber: Beans, lentils, vegetables, salads, mushrooms, nuts, seeds. I like to avoid high sugar foods like fruit: apples, oranges, bananas, pears, and so forth, because the sugar grows “bad” bacteria in the colon.

What happens if I get hypoglycemia?
A: If your metabolism is based on glucose, you will probably get hypoglycemia (low blood sugar) until you start burning fat for energy (which can take about 3 days). You may feel faint, dizzy, fatigued, tired, and may even have a headache. This is normal as your body may take a few days to switch to fat-burning. By the fourth day, you will feel much better. Be sure to sit or lie down for the few minutes it takes to get over the symptoms.

Can I take medications while fasting?
A: Most medications should not be stopped. You must be careful when taking blood pressure or diabetes medications – monitor your blood pressure and blood glucose levels, because they may drop too low. It may be important to work with your doctor to assess medication needs. If you are on medications, you can take them with a small amount of water.

Should I continue to take my supplements while fasting?
A: Supplements are food, and they are not needed during fasting. It’s good to take a break from them.

Why is fasting better than just eating less?[9]
A: While just eating less can induce autophagy, where the body removes toxins and waste products, dead and dying cells, and cancer cells. the empty stomach produces a hormone called GHRELIN, which is the “hunger hormone.” Ghrelin is “growth hormone releasing hormone” that initiates the anabolic metabolism to repair the body. People who eat multiple small meals never have an empty stomach, so they don’t get into repair mode and don’t reset their “fat thermostat.” This is why dieters gain back all the fat they lose.

What is the optimal amount of time to fast?
A: There are a lot of opinions about how much to fast. After much research and testing on myself, I am convinced that a 72-hour fast once per month is best. This is the “greatest bang for the buck” in fasting. Less time fasting gives much less benefit from ketosis and autophagy. You also get less repair. More than five days is good for weight loss and lowering inflammation, but not for those who are at their ideal weight. I have settled on eating breakfast on Friday morning and then not eating until Monday morning once per month. I still do my 5K run on Friday and Monday. (I don’t eat until after the run.) I drink a cup of water when I’m thirsty, usually 3-4 times per day. A 72-hour monthly fast is an excellent strategy for maximizing autophagy, cellular repair, improved insulin sensitivity, and disease prevention.

 

 

 

Sources:

[1] https://en.wikipedia.org/wiki/Angus_Barbieri’s_fast

[2] https://www.gutenberg.org/ebooks/63293

[3] https://valterlongo.com/fasting-mimicking-program-and-longevity/

[4] https://www.pacificneuroscienceinstitute.org/people/dale-bredesen/

[5] https://www.medicinenet.com/how_long_do_you_need_to_fast_for_autophagy/article.htm

[6] https://www.healthline.com/health/food-nutrition/dry-fasting

[7] https://www.doctorjasonfung.com/the-complete-guide-to-fasting

[8] https://drmindypelz.com/fasting-for-women/

[9] https://www.doctorjasonfung.com/the-complete-guide-to-fasting