Intermittent fasting for diabetics

Intermittent Fasting Can Reverse Type 2 Diabetes in Some Cases

Therapeutic intermittent fasting may help eliminate the need for insulin and other glucose-lowering medications in patients with type 2 diabetes, a new case series suggests.

Findings from three cases were published online October 9 in BMJ Case Reports by Suleiman Furmli, MD, of the Department of Family Medicine at the University of Toronto, Ontario, Canada, and colleagues.

The three patients had all been referred to an intensive dietary management clinic and were taking at least 70 units/day of insulin. After several months of intermittent fasting — either on alternate days or three times weekly — all three were able to discontinue insulin while improving their glycemic control. They also lost substantial amounts of body weight and had reduced waist circumferences.

“Medically supervised, therapeutic fasting regimens can help reverse type 2 diabetes and minimize the use of pharmacological and possibly surgical interventions in patients with type 2 diabetes,” Furmli and colleagues write.

The patients were given 6 hours of training on diabetes and nutrition and specific instructions for fasting. They ate only dinner and consumed unlimited very low-calorie fluids on fasting days, and ate both lunch and dinner on nonfasting days. Low-carbohydrate meals were recommended when eating meals. They followed up with the treating physician every 2 weeks.

Success Times Three

Patient 1 was a 40-year-old man with type 2 diabetes for 20 years who also had hypertension and hypercholesterolemia. At baseline he was taking metformin, canagliflozin, and long- and short-acting insulin. After fasting three times a week for 7 months, he was able to discontinue all the drugs except for canagliflozin, his HbA1c dropped from 12% to 7.5%, his weight was reduced from 84 kg to 74 kg (184 lb to 163 lb), and his weight circumference decreased from 100 cm to 87 cm (43 in to 34 in).

He reported having no difficulty with fasting and that he felt “excellent” on fasting days.

Patient 2 was a 52-year-old man with type 2 diabetes for 25 years as well as chronic kidney disease, prior renal cell carcinoma, hypertension, and hypercholesterolemia. He had been taking a fixed-dose insulin mix.

After following the same regimen as patient 1 for 11 months, patient 2 came off the insulin. His HbA1c dropped from 7.2% to 6.0%, his weight was reduced from 61 kg to 50 kg, and his waist circumference fell from 123 cm to 110 cm. He reported feeling “terrific.”

Patient 3, a 67-year-old man with type 2 diabetes for 10 years who also had hypertension and hypercholesterolemia, was taking metformin and pre-mixed insulin. After alternating fasting days for 11 months, he eliminated both diabetes medications, his HbA1c dropped from 6.8% to 6.2%, his weight dropped from 97 kg to 88 kg, and his waist circumference decreased from 123 cm to 110 cm.

He said he found the fasting “easy,” that his carbohydrate cravings had disappeared, and that his energy levels were higher.

“Therapeutic fasting is an underutilized dietary intervention that can provide superior blood glucose reduction compared with standard pharmacological agents,” the authors conclude.

The authors have reported no relevant financial relationships.

BMJ Case Reports. Published online October 9, 2018. Full text

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Ask the doctor: Will intermittent fasting reverse my type 2 diabetes?

Answer: Pre-diabetes means that your fasting blood glucose levels are higher than normal but not high enough to be diagnosed as type 2 diabetes. Once the sugars reach a sustained high level, you have moved to type 2 diabetes. Risks for type 2 diabetes include being over 45, being overweight or obese, inactivity, a family history of type 2 diabetes, being of African or Asian descent, working shift work, having polycystic ovarian syndrome (PCOS), having diabetes during pregnancy or having a baby larger then 9lbs (4kg).

The most important thing to do when you have diabetes is to lead a healthy lifestyle. The first step needs to be keeping your sugars under control. Medication prescribed for diabetes will help with this, but eating less and burning more energy are also key to blood-glucose control.

Intermittent fasting has gained a lot of popularity. It is based on the theory that on days you fast you “burn more”. Your body uses up its glucose reserves and has to start burning fat. There are some studies that show this helps reduce insulin resistance, and can be effective for weight loss. Significant weight loss and reduced insulin resistance may help reverse type 2 diabetes.

The most popular fast is the 5:2 fast. You eat normal amounts five days a week and pick two days (not consecutive) where you fast, eating only approximately 500kcal those days. The important point to make however is you must eat normally the other days. If you are a consistent overeater then any calories lost will just be made up on other days. If you find it hard to eat well in general, I think you would be much better off putting your energy into developing a healthy lifestyle and diet seven days a week. This is sustainable and will help you more over the long-term. There is also a risk of developing hypoglycaemic episodes if you fast while taking diabetic medication.

If you are overweight, aim to lose 5pc to 10pc of your body weight. Even if you are still overweight at this point it will have benefits for your health. Move more. Being active for at least 30 minutes on most days will help reduce your risk of complications of type 2 diabetes.

Eating a healthy diet is essential for weight loss and well-being. Cut out excess sugar. Avoid sugary drinks, don’t add it to tea or coffee and be aware of the sugar content of the foods you eat. Avoid saturated fats. Include healthy fats in small amounts. Your diet should include lots of fresh vegetables and carbohydrates should be whole grain.

It is important to be aware of your overall intake of carbohydrates. Remember even brown bread or pasta will break down to sugar in the body. Portion control is extremely important, whatever the food. Eat fruit in moderation, one to three portions a day.

A healthy lifestyle will not only reduce your risk of uncontrolled diabetes, it will make you feel better overall. Leading a healthy lifestyle isn’t just putting years in your life – but really life in your years.

Health & Living

Intermittent fasting may help fight type 2 diabetes

Lifestyle changes are key in the management of type 2 diabetes. Scientists believe that intermittent fasting could play an essential role.

Share on PinterestLately, intermittent fasting has become incredibly popular.

Type 2 diabetes is the most common type. The condition affects the body’s ability to produce insulin, which regulates blood sugar levels.

Diabetes is widespread in both Canada and the United States, and in the U.S., it is one of the leading causes of death.

The American Diabetes Association report that the total estimated cost of treating diabetes is now over $200 billion per year.

Lifestyle changes are crucial to managing the disease, and eating habits play a key role. Doctors normally recommend that people with diabetes follow specific diets.

The effects of a specific diet may differ from person to person, but in general, those with diabetes should avoid processed foods, artificial sweeteners, and refined carbohydrates.

Intermittent fasting could be a way to manage diabetes through diet.

What is intermittent fasting?

Intermittent fasting is a type of diet in which people cycle between periods of eating and fasting. It does not specify the foods that are allowed during the eating window.

The most common type of fasting is known as the 16:8 method, which involves fasting for 16 hours and reducing the eating window to just 8 hours. For example, a person can have dinner at approximately 7 p.m., skip breakfast the day after, and eat lunch at around 11 a.m.

Other forms involve fasting for 2 days per week, 24-hour fasting once or twice each week, and fasting every other day.

Researchers used intermittent fasting as a method to reduce the symptoms of type 2 diabetes in a new observational study conducted in Canada and published in the journal BMJ Case Reports.

The study included three men, aged 40–67, who were taking both drugs and daily doses of insulin to manage the disease. They all had high blood pressure and high cholesterol.

“The use of a therapeutic fasting regimen for treatment of is virtually unheard of,” the authors of the study write.

Intermittent fasting’s effects on diabetes

Before the study, the men attended nutrition seminars, which gave them information regarding the development of the condition, its effects on the body, and how to use diet to manage diabetes.

Then, scientists asked two of them to fast for 24 hours every other day, while the third fasted for 3 days each week. During fasting days, the men could drink low-calorie beverages such as water, tea, or coffee. In addition, they could eat a low-calorie meal in the evening.

The trial lasted 10 months in total, and the three men stuck to their schedule without encountering any difficulties. After the fasting period, the team measured their weight and blood glucose.

The results revealed significant improvement: all three lost weight, blood glucose was lower, and they were able to stop using insulin after a month from the beginning of the trial. In one case, the person stopped after only 5 days.

Two of the men also discontinued all diabetic drugs, while the third participant stopped 3 out of 4 drugs.

The authors concluded that intermittent fasting may help people with diabetes, but the study was limited to three participants. More research is needed to confirm these findings, but they are encouraging.

“This present case series showed that 24-hour fasting regimens can significantly reverse or eliminate the need for diabetic medication,” conclude the authors.

Type 2 Diabetes and Fasting: How Dangerous Could it Be?

► Fasting of any type increases the risk of hypoglycemia in patients with type 2 diabetes mellitus (T2DM) on hypoglycemic medications.

► Even with supervised hypoglycemic medication reduction, weekly supervision and education on hypoglycemia, intermittent fasting increased the rate of hypoglycemia twofold in T2DM

► Severe hypoglycemia is rare in T2DM even if intermittent fasting is undertaken.

Obesity rates and the incidence of T2DM both continue to rise worldwide. Medical treatments and low calorie diets are often employed in both conditions—to help facilitate weight loss and reduce blood sugar. The practice of fasting, consuming a no- or very low-calorie diet on consecutive days or intermittently during the week, has gained popularity but in persons with T2DM could promote dangerous levels of hypoglycemia.

BT Corely and colleagues at the Centre for Endocrine Diabetes and Obesity Research, Wellington Hospital, Wellington, New Zealand point out that dieting and fasting may be even more problematic for T2DM patients who are taking hypoglycemic medication. Few studies, they point out, have been conducted looking at intermittent fasting in patients with T2DM and none have examined the effect of hypoglycemic medications during low- or no-calorie periods on incidence of hypoglycemia.

The authors hypothesized that during a 5:2 intermittent fasting diet in individuals with T2DM on hypoglycemic medication, non-consecutive days of caloric restriction along with diabetes medication adjustment would reduce the overall risk of hypoglycemia to a greater extent than consecutive days of caloric restriction. Findings are presented in a recent issue of Diabetic Medicine.

The Study

37 patients were included in the study with 19 in the non-consecutive day fasting group and 18 in the consecutive day fasting group. The primary outcome measured was number of hypoglycemic events during 12 weeks of observation. The risk of hypoglycemia on fasting vs non-fasting days was considered a secondary outcome.

The Results

► 53 hypoglycemic events were observed during 84 observation days involving 15 subjects.

► 59% of subjects had no hypoglycemic events.

► 23 hypoglycemic events occurred over 851 fasting days (1 event per 37 days) while there were 30 events over 2257 non-fasting days (1 event per 75 days).

► No episodes of severe hypoglycemia were observed.

► Fasting conferred a twofold increase in the risk of having hypoglycemia .

► There was no difference in the risk of having a hypoglycemic event between groups .

Implications for Physicians

►Patients with T2DM who desire weight loss can benefit from very-low-calorie diets and supervised intermittent fasting programs such as 5:2 normal calorie to very-low-calorie day regimens.

►T2DM patients choosing to fast can be reassured that even though they are at higher risk for hypoglycemia on fasting days, it is unlikely that they will experience significant or severe hypoglycemic events.

►Any regimen for intermittent fasting in T2DM should be accompanied by a protocol for adjusting insulin doses and calorie intake based on blood sugars.

►Such a protocol is offered by the authors and can be found in the methods section of the complete article (link below).

Source: Corley BT, Carroll RW, Hall RM, et al. Intermittent fasting in type 2 diabetes mellitus and the risk of hypoglycemia: a randomized controlled trial. Diabet Med. 2018. Published first online 27 Feb 2018; 10.1111/dme.13595

While many consider type 2 diabetes (T2D) irreversible, fasting has been long known to reverse diabetes. In our previous post, we considered bariatric surgery. While extreme, these surgeries have proven the point that the metabolic abnormalities that underlie T2D (hyperinsulinemia, insulin resistance) can be fully reversible even after a few short weeks.

Many early studies were done with the heavy-duty Roux-en-Y surgery, which is the heavyweight champions of surgeries. The best weight loss. The most complications. This is the surgery that has ‘Go Big or Go Home’ tattooed on its massive bicep.

But even milder forms of bariatric surgery show the same reversibility of T2D. A gastric band is essentially a belt implanted around your stomach. The surgeon keeps tightening the belt so that you can’t eat. If you try to eat too much, you’ll puke it all back up. Lovely. It ain’t pretty, but it sure does work. Again, long term results are kind of iffy, but short term results are pretty good.

The results of gastric banding versus medical treatment showed a significant and pretty damn good drop in their fasting blood sugars. In other words, their T2D was reversing in a b-i-g way. Those given medicines alone basically stayed the same. They were no better than before.

Gastric banding a 500 pound patient will still reverse 20 years of diabesity within weeks. One of the main questions is why? There are many hypotheses, but essentially, it is the sudden severe restriction of all calories that causes this beneficial effect. This is the same thing as the time tested, ancient healing tradition of fasting. Fasting is the voluntary restriction of food for religious, health or other purposes (eg. hunger strikes). Is bariatrics simply a surgically enforced fast? The short answer is yes.

It’s not a progressive disease

The success of both bariatrics and fasting proves that T2D is not progressive and chronic. It’s in fact a fully reversible disease. Consider this real life example. A lady in her mid 60’s was injecting 120 units of insulin daily along with 2 grams/day of metformin (a type of medication used for T2D). She had T2D for 27 years and had been progressively using higher and higher doses of insulin in an effort to control her blood sugars. However, things were getting worse.

In desperation, she was referred to the Intensive Dietary Management Program. We started her on a regimen that included fasting under strict medical supervision. We started with a full week of fasting and immediately reduced her medications. When she was feeling well, she continued for a second week, then a third. By that time she was off her insulin. We then switched to a LCHF diet along with alternate daily fasting. It’s been over a year now, and she continues to be off all insulin and medications with a HbA1C of 5.9%. Technically, she is no longer diabetic (defined by an A1C of less than 6%).

She feels terrific – with more energy now than she has had for over a decade. Her husband was so impressed that he also started our program and has recently come off all his insulin, too.

But wait! The diabetes ‘experts’ insist that T2D was a chronic and progressive disease! How can this lady, with her 27 year history of T2D, suddenly reverse her disease and become non-diabetic? How can this possibly happen?

The answer is fasting

The answer is quite simple. The statement that T2D is chronic and progressive is just a lie. The ‘experts’ were being economical with the truth. Spinning a yarn. Pulling a ‘Bill Clinton’. But any lie, repeated often enough with enough authority, gains the semblance of truth.

But the fact that fasting reverses type 2 diabetes has been known for close to 100 years! One of the most famous diabetologists in the history of the world – Dr. Elliot Joslin wrote about it in the Canadian Medical Association Journal in 1916! In fact, he thought that it was so obvious that fasting was helpful that studies would not even be necessary. This, from the guy that Harvard University used to name its world famous Joslin Center for Diabetes.

What happened to Joslin and fasting for diabetes? Well, back then, medical science had not yet distinguished Type 1 and Type 2 diabetes back then. Fasting is not useful for type 1, and type 2 was still quite unusual back then. After the discovery of insulin in the early 1920’s, all the focus turned to it as the ‘cure’ for type 2 diabetes. While it was a major advance for type 1, it was not quite the panacea for type 2s. However, most of the interest in fasting disappeared as doctors focused on what would be their mantra for the next century – drugs, drugs, drugs. All types of dietary therapy fell into disrepute, since they were really not useful in type 1 diabetes, and have stayed there ever since.

The effect of wartime starvation on T2D also obviously highlights the effect of reducing food consumption on diabetes. During both world wars, the mortality from diabetes dropped precipitously. In the interwar period, as people went back to their accustomed eating habits, it went back up. This, of course is quite easy to understand. Since T2D is essentially a disease of excessive sugar in the body, reducing intake of sugars and carbohydrates should cause less disease.

Bariatrics or fasting?

Returning to the point that bariatrics is simply a surgically enforced fast, you can directly compare the effects of fasting and bariatrics. One fascinating study assessed patients waiting for bariatric surgery who were given a period of fasting beforehand. The reasoning was that many morbidly obese patients had enormous fatty livers. If you could somehow reduce this fatty liver and reduce their weight somewhat, the risk of surgical complications would be reduced since there is now more room to work within the surgical field.

The reduction in liver size would make working in the abdominal cavity much easier, with better vision. Since many of these procedures are done laparascopically, being able to see better is a huge benefit. Also, with less abdominal distention, abdominal wound healing was significantly improved. Therefore, fasting before surgery makes total sense.

In the meantime, you could compare both sugar control and weight loss during the fasting period and also during the post surgical period. Since bariatrics is considered the heavy weight champ, this was a real David vs Goliath battle (Fasting vs Surgery).

In the graph below, you can see the results. In the first graph, fasting caused 7.3 kg weight loss compared to only 4 kg for surgery. The second graph shows the overall ‘glycemia’ or the total amount of sugar in the blood over the day. During fasting, there was far less sugar in the blood (1293 vs 1478). On both counts you can see that the fasting was actually significantly better than the surgery! Blood sugars came down faster, as did weight. David (fasting) did not simply beat Goliath (bariatrics), he beat him like a rented mule.

If all the benefits of bariatric surgery accrue because of fasting, why not simply do the fasting and skip the surgery? The standard answer is that people cannot do the fasting without the surgical enforcement. But have they ever tried? How do you know that you cannot fast for an extended period of time if you have never tried it? Shouldn’t you at least give it a shot before giving up?

But my main point is again, not to criticize or praise surgery. Rather my point is this. Fasting reverses type 2 diabetes. Rather than the chronic and progressive disease that we have been promised, instead T2D turns out to be a treatable and reversible condition. Both practices of fasting and bariatric surgery prove the point. This is a curable disease. Type 2 diabetes is entirely reversible. This changes everything. A New Hope arises.

Jason Fung

Why Are Fasting Glucose Levels High?

Pictured Recipe: Air-Fryer Crispy Chickpeas

Stumped by high fasting blood glucose results? Join the club. “It just doesn’t compute. When I snack before bed, my fastings are lower than when I limit my night nibbles,” says Pete Hyatt, 59, PWD type 2.

“It’s logical for people to point the finger for high fasting blood sugar numbers at what they eat between dinner and bed, but surprisingly food isn’t the lead villain,” says Robert Chilton, M.D., a cardiologist and professor of medicine at the University of Texas Health Science Center at San Antonio. The true culprit is compromised hormonal control of blood glucose levels.

Related: 12 Healthy Ways to Lower Your Blood Sugar

The Essential Hormones

During the years (up to a decade) that type 2 diabetes develops, the hormonal control of blood glucose breaks down. Four hormones are involved in glucose control:

Insulin, made in the beta cells of the pancreas, helps the body use glucose from food by enabling glucose to move into the body’s cells for energy. People with type 2 diabetes have slowly dwindling insulin reserves.

Amylin, secreted from the beta cells, slows the release of glucose into the bloodstream after eating by slowing stomach-emptying and increasing the feeling of fullness. People with type 1 and type 2 diabetes are amylin-deficient.

Incretins, a group of hormones secreted from the intestines that includes glucagon-like peptide 1 (GLP-1), enhance the body’s release of insulin after eating. This in turn slows stomach-emptying, promotes fullness, delays the release of glucose into the bloodstream, and prevents the pancreas from releasing glucagon, putting less glucose into the blood.

Glucagon, made in the alpha cells of the pancreas, breaks down glucose stored in the liver and muscles and releases it to provide energy when glucose from food isn’t available.

How the Essential Hormones Work in the Body

When diabetes is not present, the body handles the changing supply of and demand for glucose (the energy from food) 24 hours a day. This system involves the four hormones — what we’ll call the messengers — and a continuous feedback loop that moves messages between the brain, gut, pancreas, and liver.

Here’s how the system works in people without diabetes:

When fasting: As blood glucose falls after peaking from the last food eaten, the pancreas puts out less insulin hormone. At the same time, two other hormones wane: amylin and glucagon-like peptide 1 (GLP-1), which help store and use glucose. A fourth hormone, glucagon, kicks into gear to offer a constant flow of glucose. Glucagon sends messages to the liver and muscles to make glucose from stored energy.

After eating: Food raises blood glucose and sends a message to the intestines to release GLP-1, which primes the insulin and amylin spigots. These hormones help cells use the glucose from food to fuel the body. The glucagon spigot turns off because there’s little need for glucose from the liver or muscles when food is available. The impact of food on blood glucose, even for a large, high-fat meal, lasts less than six hours.

The Dawn Phenomenon and Somogyi Effect

Here are two other situations that may cause high fasting blood glucose levels:

Dawn phenomenon happens as part of the body’s normal circadian rhythm to wake up and get going. Hormones, such as growth hormone and cortisol, are released and raise glucose. Without diabetes, the body simply responds to this early morning effect by putting out more of the hormones that keep blood glucose in control. That doesn’t happen when you have type 1 or type 2 diabetes.

Somogyi effect is very high fasting blood glucose thought to be caused by the liver making a lot of excess glucose in response to hypoglycemia (low blood glucose) during the night. Somogyi effect is uncommon in type 2 diabetes. There’s controversy as to whether it even exists with the rapid- and long-acting insulins available today.

Hope Warshaw, R.D., CDE, coauthored Real-Life Guide to Diabetes (American Diabetes Association, 2009) and is a contributing editor to Diabetic Living.

Planned intermittent fasting may help reverse type 2 diabetes, suggest doctors

And cut out need for insulin while controlling blood glucose

Planned intermittent fasting may help to reverse type 2 diabetes, suggest doctors writing in the journal BMJ Case Reports after three patients in their care, who did this, were able to cut out the need for insulin treatment altogether.

Around one in 10 people in the US and Canada have type 2 diabetes, which is associated with other serious illness and early death. It is thought to cost the US economy alone US$245 billion a year.

Lifestyle changes are key to managing the disease, but by themselves can’t always control blood glucose levels, and while bariatric surgery (a gastric band) is effective, it is not without risk, say the authors. Drugs can manage the symptoms, and help to stave off complications, but can’t stop the disease in its tracks, they add.

Three men, aged between 40 and 67, tried out planned intermittent fasting to see if it might ease their symptoms. They were taking various drugs to control their disease as well as daily units of insulin. In addition to type 2 diabetes, they all had high blood pressure and high cholesterol.

Two of the men fasted on alternate days for a full 24 hours, while the third fasted for three days a week. On fast days they were allowed to drink very low calorie drinks, such as tea/coffee, water or broth, and to eat one very low calorie meal in the evening.

Before embarking on their fasting regime, they all attended a 6-hour long nutritional training seminar, which included information on how diabetes develops and its impact on the body; insulin resistance; healthy eating; and how to manage diabetes through diet, including therapeutic fasting.

They stuck to this pattern for around 10 months after which fasting blood glucose, average blood glucose (HbA1c), weight, and waist circumference were re-measured.

All three men were able to stop injecting themselves with insulin within a month of starting their fasting schedule. In one case this took only five days.

Two of the men were able to stop taking all their other diabetic drugs, while the third discontinued three out of the four drugs he was taking. They all lost weight (by 10-18%) as well as reducing their fasting and average blood glucose readings, which may help lower the risk of future complications, say the authors.

Feedback was positive, with all three men managing to stick to their dietary schedule without too much difficulty.

This is an observational study, and refers to just three cases–all in men. As such, it isn’t possible to draw firm conclusions about the wider success or otherwise of this approach for treating type 2 diabetes.

“The use of a therapeutic fasting regimen for treatment of is virtually unheard of,” write the authors. “This present case series showed that 24-hour fasting regimens can significantly reverse or eliminate the need for diabetic medication,” they conclude.
Notes for editors
Myth exploded: Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin doi 10.1136/bcr-2017-221854
Journal: BMJ Case Reports

Keeping up with the latest “diets” has never been easy. There’s always a new crop of them that pop up, and many become all the rage for a while, garnering avid followers and fierce proponents. And when it comes to delivering on results, such as weight loss, most diets work. Whether you can stick with a diet for a given length of time is another story, however.


Diets that are hot right now include the ketogenic, or keto, diet, low carb, the carnivore diet and intermittent fasting. The very word “fasting” is probably less than appealing, as it pretty much means you don’t eat or drink anything (except perhaps water) for a specified amount of time. Most health-care professionals don’t routinely recommend this for health purposes. But intermittent fasting is different. Is it safe to do if you have diabetes? And is it something you should try?

What is intermittent fasting, anyway?

Intermittent fasting has has grown in popularity over the past few years, in part, due to two books: The Fast Diet by Dr. Michael Mosley and Mimi Spencer, and The Overnight Diet by Caroline Apovian, MD. Intermittent fasting essentially means that you skip a meal or severely restrict calories on certain days of the week with the intention of losing weight, controlling blood glucose, and/or decreasing heart disease risk. But on the other days of the week, you can pretty much eat what you want (within reason, of course). For many people, this concept sounds appealing. Limiting calories for a couple days a week doesn’t sound that bad if you can eat what you want the rest of the time.

On The Fast Diet, also called the The 5:2 Diet has you eat between 500 and 600 calories (women get 500 calories, men get 600 calories) for two days out of the week, spread over two meals of about 250 to 300 calories. These fast days should not be right in a row, and your food choices ideally should be more plant-based and emphasize protein. The premise is that after several hours of fasting, the body burns up its carbohydrate stores and shifts to burning fat for fuel. Many claim that intermittent fasting also helps to blunt appetite.

The Overnight Diet emphasizes getting enough sleep; a lack of sleep can disrupt metabolism, making it hard to lose weight. Sufficient sleep, according to the author, will reduce hunger pangs. The diet part of this involves drinking homemade smoothies once a week, and eating a low-calorie, high-protein diet the remaining six days of the week.

Does intermittent fasting work?

Is intermittent fasting just another passing fad? Maybe, but there actually is some credible science behind fasting. Restricting calories in the diets of animals appears to increase their lifespan, for example. A team of researchers in the UK looked at the various approaches to intermittent fasting, with a focus on how they might help (or hinder) those with Type 2 diabetes and obesity. They found that intermittent fasting is as effective as or even more effective than simply cutting calories to lose weight.

They also found that intermittent fasting has other health benefits, including reducing inflammation, lowering blood pressure, lowering heart rate, lowering cholesterol and reducing insulin resistance. This unique approach may even help prevent the development of Type 2 diabetes. Followers of the diet also believe that intermittent fasting can prolong your life and prevent Alzheimer disease.

A recent study out of New Zealand involved 41 participants with Type 2 diabetes who were assigned to the 5:2 fasting diet. They could eat what they wanted for five days a week, and then “fasted” for the next two days (“fasting” was actually a 600-calorie diet for men, and a 500-calorie diet for women). Half of the group were instructed to fast for two days in a row during the week, while the other half fasted on non-consecutive days.

The results? After 12 weeks, A1C levels dropped in both groups from 8.4 percent to 7.8 percent in the consecutive group and from 8.2 percent to 7.5 percent in the non-consecutive group. Both groups lost about the same amount of weight (on average, 8 pounds in the consecutive group, 7 pounds in the non-consecutive group).

You might be thinking, “That’s great — they lost weight!” Yes, they did, but the amount of weight lost over 12 weeks, while commendable, is less than what most lower-calorie eating plans recommend (a loss of between 1 and 2 pounds per week). In addition, in this study, the risk of hypoglycemia (low blood glucose) increased during the fasting days, and that’s not surprising. What’s interesting, however, is despite the hypoglycemia, the participants still managed to lose weight and lower their A1C. (Frequent hypoglycemia may lead to weight gain in some people due to having to treat the lows with carbohydrate).

In another study, published in BMJ Case Reports, three men with Type 2 diabetes treated with insulin between the ages of 40 and 67 tried intermittent fasting for 10 months. Two of the men fasted every other day for 24 hours, while the third man fasted for three days a week. “Fasting” in this study consisted of a low-calorie meal at night and non-caloric beverages. All of the men were able to stop taking insulin between 5 and 18 days into the regimen. Two of the men were able to discontinue their other diabetes medicines altogether. In addition, they all lost weight (between 10 and 18 percent), reduced their weight circumference and lowered their A1C. Hypoglycemia wasn’t a concern.

Is intermittent fasting for you?

Intermittent fasting may seem intriguing, if not downright appealing. But before you jump on the fasting bandwagon, realize that research this area is still relatively new, at least with humans. It’s true that the few studies thus far look promising — not just for A1C and weight reduction, but for lowering blood pressure and cholesterol, as well. But there aren’t long-term studies to indicate if this dietary approach is safe, effective or sustainable.

A review of 40 studies showed that a typical weight loss over a 10-week period ranged from 7 to 11 pounds. That’s pretty good, but not earth-shattering. The review also showed that intermittent fasting isn’t necessarily any easier to follow than other dietary approaches. In a randomized controlled trial of 100 obese individuals who did either alternate-day fasting or a calorie-restricted diet with three meals per day, there were no significant differences between the two groups in the amount of weight lost or regained, fasting glucose, fasting insulin, heart rate, blood pressure and total cholesterol (although LDL was higher in the alternate fasting group).

The appeal of being able to lose weight and decrease (and maybe even discontinue) some or all of your diabetes medication is certainly strong. But what DO you eat on an intermittent fasting plan? A sample 500-calorie menu from The Fasting Diet is steel-cut oatmeal with 1/2 cup of blueberries for breakfast, and then chicken stir-fry made with 5 ounces of chicken and some vegetables, along with a tangerine for dinner. That’s it. Would that hold you?

Could intermittent fasting be harmful?

Well, that depends. If you take insulin or sulfonylurea drugs to control your blood glucose, intermittent fasting can considerably raise the risk of low blood glucose unless you make appropriate adjustments. Intermittent fasting is not suitable for:

• pregnant women or women who are breastfeeding
• people under the age of 20
• people who are underweight
• people who have an eating disorder

It may also not be good for people who take certain types of medicines, such as beta-blockers.

Side effects of this diet include:

• extreme hunger
• irritability
• weakness
• shakiness
• fatigue

There’s also some concern that intermittent fasting may trigger binge eating. Another question to ask yourself: Can you really stick with this way of eating? It may sound simple to just eat 500 calories for two days a week, but 500 calories isn’t all that much. On those days, you’re likely to feel tired, grumpy, anxious and irritable. You also may not sleep well and your breath might not exactly smell like a bed of roses. You may have difficulty concentrating and performing at work or school.

If you’d like to give intermittent fasting a try, talk it over first with your health-care provider and decide together if it’s something that could work for you. If you’re determined to give it a go, at least inform your provider of your intent and discuss a plan for possibly decreasing your diabetes medication doses to prevent or limit hypoglycemia. Consider meeting with a registered dietitian who supports your goals to work out a plan (not all intermittent fasting diets follow the 5:2 approach). And if you have tried this, feel free to share your experience!

Want to learn more about diabetes and fasting? Read “Can Fasting Help Diabetes?” and “Fasting During Ramadan.”

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