Researcher says a fasting diet can encourage cells to produce insulin again. Others aren’t quite as sure.

Can simply eating less food periodically cure someone of diabetes?

Can such a diet cause cells that have been hampered from producing insulin to start producing it again?

At least one researcher seems to think so.

Healthy diets have long been promoted as a way of lowering your risk of diabetes, and a careful diet is necessary for avoiding blood sugar spikes for those who already have the disease.

Valter Longo, PhD, the director of the Longevity Institute at the University of Southern California (USC) Leonard Davis School of Gerontology, has long been a proponent of the fasting diet.

In a study published late last month in the journal Cell, Longo and fellow researchers concluded a fasting diet promoted the growth of new pancreatic cells, which help produce insulin, in mice with type 1 and type 2 diabetes.

Human cells exposed to the diet in a dish also produced increased insulin, suggesting it could alleviate diabetes in humans.

Longo hopes to begin human trials of the fasting diet later this year.

Read more: Get the facts on diabetes »

There are plenty of questions left to be answered.

One is whether only a portion of patients — perhaps those who recently developed diabetes and haven’t been insulin-deficient as long — respond to the diet.

“We don’t know,” Longo told Healthline. “We’ll see if the only ones who respond are the more recent ones — or nobody.”

Longo, who also partially owns a food company that sells meal plans to help people who want to follow a fast-mimicking diet. He’s conducted past research that has found this type of diet might reduce the risk for cancer, heart disease, and other age-related ailments.

Those ties also raise some questions.

“Any time it seems like something can fix everything, that’s always a worry. And then when there’s products involved,” says Deborah Greenwood, PhD, RN, president of Deborah Greenwood Consulting, specializing in diabetes and digital health, and past president of the American Association of Diabetes Educators. “But I wouldn’t want to say something is bad just because it’s unique. We just need long-term studies with a significant amount of people.”

Other recent research has also raised the possibility of reversing diabetes through diet.

Another short-term study, published last week, found that 10 weeks of a personalized, ketogenic diet that was overseen remotely by medical professionals led to improved control over blood sugar levels and weight loss in people with type 2 diabetes.

The ketogenic diet includes low amounts of carbohydrates, which have the most impact on blood sugar.

But that study, backed by a new start-up that calls itself an “online specialty medical clinic that reverses type 2 diabetes without medications or surgery,” has product ties, too.

“I never liked the word ‘reversal’ in terms of diabetes,” Greenwood told Healthline.

She says the only way to truly reverse it would be bariatric surgery, in which a portion of the stomach or intestines is removed. But she says she knows people with diabetes who have followed a ketogenic diet and love it.

“It’s just really hard to live in the world and engage in typical life when you’re so restricted, and there’s no long-term data to show if it’s sustainable or healthy,” she said.

Read more: Artificial pancreas may be the future of diabetes treatment »

Greenwood said Longo’s study could be different because it suggests it could be possible to change a person’s cells not simply behavior, as in the ketogenic study.

But it would still likely require some behavior changes because of the careful monitoring required by the new diet.

“Most people who are on insulin are highly engaged, and some aren’t,” she said. “My guess would be someone who would take on a rigid diet would be engaged. But maybe not. The mice didn’t have to do too much in their lives. They didn’t have to go to work. They had fairly easy routines.”

Undertaking those sorts of diets on your own — particularly if you’re dependent on insulin medication — can be dangerous, although even before these studies there were a number of claims online of people using fasting or starvation diets to reduce the impacts of the disease.

As for his formula, Longo wouldn’t say what exactly the diet consists of.

“We don’t talk about the diets because we don’t want people to improvise at home,” he told Healthline. “It’s quite dangerous the way it’s done right now for diabetic patients, especially those on insulin.”

Human trials, he says, would be undertaken in a hospital setting with careful oversight and protocols.

But his goal is to one day have the diet approved for home use.

He describes a box with strict instructions that people could take home, although it still wouldn’t likely be available to those using insulin.

So, however the research advances, the best diet will still be the one that helps keep diabetes at bay in the first place. Experts say avoiding processed carbs, sugary drinks, and red meat as much as possible is a great start.