Fasting can reverse type 2 diabetes, a team of scientists behind a small study have claimed.
For their preliminary study, researchers asked three patients with type 2 diabetes to follow intermittent fasting programs and found they were able to safely stop using insulin to control their blood sugar levels.
Diabetes is a major health issue in the U.S. closely linked to the obesity epidemic. Around 30.3 million people in the U.S. have the condition according to the latest figures from 2015: including 7.2million who are undiagnosed, according to the American Diabetes Association.
Most people have type 2 diabetes, where the body develops insulin resistance causing blood glucose levels to shift out of the normal range.
Bariatric surgery, where the size of the stomach is reduced to cut the amount of calories a person consumes, is one method for treating type 2 diabetes, the authors of the study published in the journal BMJ Case Reports noted. But such procedures can be expensive and risky.
Researchers in Canada hypothesized similar results could be achieved by cutting calorie intake with fasting.
The three participants who took part in the study had been referred to the Intensive Dietary Management clinic in Toronto, Canada, and were each using insulin daily to manage their type 2 diabetes.
The participants were a 40-year-old man diagnosed with diabetes 20 years prior to the start of the study; a 52-year-old man diagnosed 25 years earlier; and a 67-year-old man diagnosed for 10 years.
As quitting insulin can cause dangerous shifts in blood glucose levels for diabetics, the team gave the participants detailed instructions on how to monitor their blood during the study. The participants were told to stop fasting if they felt unwell.
Read more: 16:8 fasting diet linked to weight loss and health benefits in study
On fast days, participants only ate dinner and were allowed to consume as many low-calorie drinks, such as water, coffee, tea, and bone broth, as they wanted. They were told to consume lunch and dinner on the other days. Patients one and three fasted three times a week, while patient two cut their food on alternate days.
Patients one and three completed 24-hour fasts every other day, while patient two fasted three times a week. During this time, researchers measured health markers like blood sugar and weight.
By the end of the study (which patient one followed for seven months and two and three for 11 months) all of the participants had lost weight. Patients two and three no longer needed any medication to treat their diabetes, while patient one required no insulin but continued taking one oral medication.
Study author Dr. Jason Fung, of the Department of Medicine, Scarborough Hospital, Canada, told Newsweek: "This study show that a dietary intervention, therapeutic fasting, has the potential to completely reverse type 2 diabetes, even when somebody has suffered with the disease for 25 years. It changes everything about how we should treat the disease."
The study was carried out in a small sample size so needed to be corroborated in a larger population, but if the same results can be replicated, the public health implications could be huge, said Fung. Such a treatment could chip away at the estimated $327 billion the disease is believed to have cost the U.S. in 2017, according to the American Diabetes Association.
"We can treat type 2 diabetes with a free dietary intervention, that is available to everybody, for free. The amount of savings for the public health system would be astronomical, and patients would be healthier. We are talking about millions of dollars every year, if we can simply spread the right information to the people that need it," Fung said.
"It is the ultimate in patient empowerment, and the ultimate in savings for public health."
However, Dr. Faye Riley, Research Communications Officer at Diabetes U.K. who was not involved in the research, warned the study does not provide enough robust evidence to suggest intermittent fasting is an effective way of achieving remission in type 2 diabetes.
Riley cautioned: "Intermittent fasting can cause blood sugar levels to drop dangerously low especially if you're taking certain medications, including insulin. We'd recommend that anyone with type 2 diabetes who is considering making drastic changes to their diet speak to their health care professional first."
Joy Cornthwaite, a diabetes educator at the University of Texas Health and Science Center at Houston, told Newsweek the study opens an important dialogue on diabetes care.
But she added it "does not speak to the entirety of diabetes care and management in a way that is truly generalizable."
"It is because of this that we must temper our response regarding intermittent fasting as an alternative to insulin and or medication therapy, and instead focus on intermittent fasting as a tool for improved diabetes management," she said.
"What is perhaps more important to note is that all people, regardless of those characteristics we cannot change, like family history, sex, age and ethnicity, can benefit from healthy lifestyle and when needed medications–to prevent and manage diabetes."
Commenting on the study he was not involved in, Dr. James Catterson of the Institute of Healthy Aging at University College London told Newsweek taking three diabetic men off insulin within a month is "quite a remarkable feat."
"I would be interested to know if these patients managed to continue their diets, and if not, did their diabetes return?"
He argued the biggest downfall of the observational study is the small sample size, as "three people is nowhere near enough to begin making clinical recommendations.
"But this is a 'case study' and these studies are meant to inform future larger studies."
In recent years, studies supporting and questioning the safety and health benefits of fasting diets have been piling up. And regimes such as 5:2 and 16:8 have been growing in popularity, regardless of a lack of concrete evidence to definitively prove they are beneficial. As such, the consensus among experts on such regimes remains unclear.
One such study presented at the European Society of Endocrinology annual meeting before it was peer-reviewed linked fasting to an increased risk of developing diabetes.
Rats who were put on alternate day fasting diets lost weight, but fat collected in their stomachs, and their pancreas cells became damaged.
This article has been updated with comment from Joy Cornthwaite and Dr. James Catterson.
Uncommon Knowledge
Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Kashmira Gander is Deputy Science Editor at Newsweek. Her interests include health, gender, LGBTQIA+ issues, human rights, subcultures, music, and lifestyle. Her ... Read more
To read how Newsweek uses AI as a newsroom tool, Click here.
