People with type 2 diabetes are better off doing intermittent fasting to lose weight rather than cutting their calories, scientists have found.
Those with type 2 diabetes who only ate during an 8-hour window of the day—between noon and 8 p.m.—lost more weight over a 6-month period compared to those who reduced their calorie intake by 25 percent, according to a new study published in thejournal JAMA Network Open.
The intermittent fasters were also found to have no difference in blood sugar levels across the study, indicating that this is a safe weight loss approach for those with type 2 diabetes.
"Time-restricted eating [intermittent fasting] involves eating all food within an 8-hour window and fasting the remaining time with water or calorie-free drinks. During the eating window, there is no need to count calories. Intermittent fasting leads to a reduction of calorie intake (because there is less time to eat), which then leads to weight loss," Krista Varady, a professor of kinesiology and nutrition at the University of Illinois, Chicago and co-author of the paper, told Newsweek.
Type 2 diabetes is caused by a person's cells failing to respond to the hormone insulin. Insulin is released by the pancreas and triggers the body's cells to start using up the sugar in your bloodstream. Type 1 diabetes means the pancreas does not produce enough insulin, while type 2 occurs when the cells stop responding to insulin.
These conditions both lead to high blood sugar, which can cause serious health issues like vision loss, kidney damage and heart disease. One in 10 Americans have some form of diabetes, and this is expected to rise to as many as 1 in 3 by 2050, according to the paper.
The study looked at the diets of 75 participants with type 2 diabetes—divided into a control group, a calorie reduction group, and an intermittent fasting group—and measured how their weight, waist circumference and blood sugar levels changed over six months. The authors discovered for the first time that intermittent fasting is just as safe for those with type 2 diabetes as calorie cutting.
"Our study is the first to show that fasting is just as safe as standard care (daily calorie counting) in people with type 2 diabetes. The time-restricted eating diet did not result in increased rates of hypoglycemia (low blood sugar) and produced few adverse events," Varady said.
"However, before starting a fasting diet, people with type 2 diabetes will need to contact their doctors for medication adjustments. Their doctors will need to reduce the medications that result in low blood sugar (such as insulin and sulfonylureas).
"I don't think fasting is better than calorie counting; it's just another option for people with type 2 diabetes," Varady said. "A lot of people with type 2 diabetes are sick of being prescribed a calorie-counting diet, so time-restricted eating serves as a refreshing alternative. Some people may find it easier to count time instead of counting calories to lose weight. But no matter what, people should follow the diet that they can best fit into their personal lifestyles."
The authors suggest in the paper that the intermittent fasters found it easier to follow their regimens than the calorie restrictors, and this may have been because many of them had already struggled with calorie cutting at some point beforehand.
"The risks vary depending on the type of diet," Varady said. "Some people report headaches or constipation with fasting. This often lasts only the first couple weeks of the diet and can be avoided by staying hydrated. In those with type 2 diabetes, there is a risk of low blood sugar (as mentioned above), depending on the types of medications prescribed," Varady said.
The study was fairly small in scale, however, so the authors state that more data and research are needed in this field. Additionally, the study did not look at how calorie cutting and intermittent fasting differ between non-diabetics.
"Both intermittent fasting and calorie restriction are equally effective for weight loss in people without diabetes. We [previously] published a 12-month study this summer showing that people with obesity who follow time-restricted eating lose the same amount of weight as daily calorie restriction (5 percent, about 13 pounds over 1 year)," Varady said.
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Uncommon Knowledge
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Jess Thomson is a Newsweek Science Reporter based in London UK. Her focus is reporting on science, technology and healthcare. ... Read more
