Intermittent fasting was the most-searched diet online last year and the second-most-popular choice of the 38% of Americans aged 18 to 80 who said they followed a specific eating plan.
There are now apps to guide you in intermittent fasting, plus books, blogs and articles touting its success. Unlike some other popular diets, however, there’s also a growing collection of scientific evidence behind it, especially in relation to diabetes and the collection of conditions known as metabolic syndrome.
“I’m starting to see more talk about intermittent fasting and even fasting at the American Diabetes Association meeting,” said John White, chair of the Department of Pharmacotherapy and R. Keith Campbell Distinguished Professor in Diabetes Care at the Washington State University College of Pharmacy and Pharmaceutical Sciences.
“I’m fascinated by it,” he added. “There’s a notion in clinical medicine that’s not often spoken of and it’s called de‑prescribing. There are many studies and reports where people can dramatically reduce the medications they’re on just by altering their lifestyle, and intermittent fasting is one approach.”
Intermittent fasting can mean dramatically restricting calories a couple days a week, or consuming all daily calories within a 6‑, 8‑ or 10‑ hour window each day.
A small study published last year by one of the leading researchers in intermittent fasting—Jason Fung, M.D., a kidney specialist in Canada—showed that three patients with diabetes were all able to discontinue insulin within a few weeks of following a medically monitored fasting regimen. On fasting days, the patients ate only dinner, while on non‑fasting days they ate lunch and dinner, focusing on low-carbohydrate meals. All reported feeling good while on the regimen, and all lost weight. Two patients discontinued their diabetic medications entirely, while the third was able to discontinue three of four medications.
A separate, NIH‑funded study published recently in Cell Metabolism found that 19 participants, all diagnosed with metabolic syndrome, lost weight, reduced their waist circumference and lowered their cholesterol and blood pressure over three months. Next up is a larger study involving 100 people with metabolic syndrome.
How does not eating improve your health?
The end result is that you’re consuming fewer calories, White said. But fasting also gives your pancreas a rest.
The food pyramid that many people still follow emphasizes complex carbohydrates, with smaller amounts of fat and protein. In addition, eating small, frequent meals is common nutritional advice, including for people with diabetes. But all that eating stresses the pancreas, which produces insulin and leads to insulin resistance and higher blood sugar. When you stop eating for periods of time, insulin secretion drops, promoting a reversal of insulin resistance, White said.
“You have a period of time where you don’t have a system that’s just awash in glucose,” he said.
White cautioned that anyone taking medication who’s considering following an intermittent fasting plan first check with their healthcare professional. And he said everyone has a different physiology, so what works for one person may not for another.
But he believes there’s room for “individual free thinkers” to consider alternatives to standard nutritional advice for people with diabetes.
“What happened when we moved from the diet we were consuming in the 1970s to this low‑fat, high‑carb diet, obesity skyrocketed,” White said. “There are other reasons for that too, but I think the food pyramid has been called into question.”