Intermittent fasting is enjoying a moment of great popularity in American homes – by some accounts, matching the popularity of calorie counting and plant-based diets.
The call ?
Research suggests that simply having less time to eat can lead people to reduce the amount they ultimately consume, without having to track every calorie.
Now, new research strengthens the argument that intermittent fasting – specifically limiting when you eat to a given time slot during the day – can be a safe and effective strategy for managing diabetes. type 2.
The study, published Friday in JAMA open, reveals that people with type 2 diabetes can lose weight and manage their blood sugar levels by eating only within an 8-hour window each day.
“I think it’s pretty interesting data,” says Dr. Joanne Bruno, an endocrinologist at NYU Langone Health, who was not involved in the trial.
Although still an emerging area, a growing number of clinical trials have shown that time-restricted eating can improve metabolic health and lead to weight loss. But few of these studies have focused specifically on type 2 diabetes.
The findings add evidence that time-restricted eating can help people with high blood pressure, low blood sugar and other problems affecting cardiovascular and metabolic health, says Dr. Pam Taub, a cardiologist at the University of California San Diego.
“I think you get the most bang for your buck with this type of population,” says Taub, who has also published studies on time-restricted eating.
A simpler alternative
The study, based at the University of Illinois at Chicago, lasted six months and included 75 adults with type 2 diabetes.
The study authors say this is the first randomized controlled trial to directly compare time-restricted eating to calorie counting in patients with type 2 diabetes, examining the effects on body weight and l ‘A1C, a test that shows blood sugar levels over the past three months.
Overall, the study found that time-restricted eating led to about the same improvements as counting calories in A1C levels. Both groups experienced a decline of more than 0.7% from baseline over a six-month period.
Given that most medications used for diabetes will reduce this figure by around 1%, Bruno says this represents a “significant change and may have significant clinical benefits.”
The difference in weight loss was the most remarkable result.
Those who only ate between noon and 8 p.m. ended up losing nearly twice as much weight as those who counted their calories.
“I was surprised,” says Krista Varady, a professor of nutrition at the University of Illinois and lead author of the study. She notes that her previous studies showed the same amount of weight loss as counting calories, no more.
“They didn’t need to count calories or carbs or anything like that,” she says. “They ended up reducing their calorie intake just by eating during that 8-hour window.”
The study included three groups: controls who made no changes to their diet, those who were asked to count calories and reduce their intake by about 25%, and the time-restricted eating group. .
On average, those who continued eating for 8 hours lost about 10 pounds and lost more fat than the group who counted calories, who lost a total of about 6 pounds.
Varady says they chose the noon to 8 p.m. window because observational studies show that’s when most people who practice intermittent fasting prefer to eat.
“They really found time-restricted eating to be a nice and refreshing alternative,” she says.
Many study participants said in interviews that they had been advised for years to count calories and were disappointed by that approach, Varady says.
Benefits Go Beyond Weight Loss
Although it’s the largest clinical trial to date in type 2 diabetes, it’s still considered “pretty small,” but it was done well, says Benjamin Horne, an epidemiologist at the Intermountain Heart Institute from Salt Lake City and assistant professor at Stanford University..
“I would say this is the best study done in this population to date, so I think we can be confident that there are potential benefits,” he says.
Indeed, Varady and his co-authors acknowledge that this study needs to be followed up with larger trials and caution that the weight loss results should not be interpreted as proving that it is better to eat for limited periods.
“It’s not a one-size-fits-all approach,” she says. “We’re just showing that time-restricted eating is another option.”
Horne highlights some of the study’s strengths. It included a diverse patient pool: a majority of participants were black and about a third were Hispanic. And those who followed a time-restricted diet had good compliance, sticking to the 8-hour window on average about six out of seven days a week.
Finally, although weight loss groups meet regularly with dietitians, the study offers a practice that people can replicate even if they are not participating in a clinical trial.
“It’s very easy to follow a fasting diet,” he says, “you don’t need a prescription to do it. It doesn’t cost anything.”
In an era of blockbuster drugs for weight loss and diabetes, Taub says the study adds to the evidence that this lifestyle intervention can also help.
“It’s not one or the other,” Taub says. “One of the things I look for with my patients with type 2 diabetes is, how do I minimize drug therapy and maximize lifestyle?”
In fact, Taub’s work has shown that for people with metabolic syndrome, a 10-hour eating window not only improves their ability to manage their blood sugar, but also reduces other parameters like blood pressure and cholesterol.
A study of shift workers found that intermittent fasting, even if done late in the evening, can still confer benefits. “It’s about giving your body that period of fasting, that metabolic rest,” she says.
What the research suggests, she says, is that time-restricted eating may provide greater metabolic benefits than would be expected from simply losing a given amount of weight.
For people with type 2 diabetes, Taub and Bruno say patients should not begin intermittent fasting without medical supervision.
For example, in the JAMA open In the study, some participants had to adjust their medications based on their blood sugar test.
Bruno says concerns about hypoglycemia from fasting appear to be one reason why there haven’t been more studies on people with type 2 diabetes until now.
While there are still safety questions that need to be investigated, especially for those taking insulin, she says overall it appears safe and effective.
And it is more and more a tool that she offers to her patients.
“Many feel liberated in some way by this dietary strategy,” she says. “I hope the time-limited feeding will be rewarded.”
Carmel Wroth edited this story.