Time-restricted eating helps control blood sugar in Type 1 diabetes, clinical study finds

Time-restricted eating could present a safe and effective method to control blood sugar in adults with Type 1 diabetes, according to findings from a new study. 

“This is the first study to examine the effects of intermittent fasting on people with Type 1 diabetes, and the results are extremely promising,” highlights study lead author Krista Varady, a kinesiology and nutrition professor specializing in intermittent fasting who conducted some of the first human studies on the subject.

The researchers highlight that Type 1 diabetes is a chronic condition of low or no insulin production, which affects less than 1% of people in the US.

They note that time-restricted eating has emerged as a popular approach for weight loss; however, its efficacy and safety in Type 1 diabetes have previously not been evaluated.

The study aimed to examine whether time-restricted eating is more effective for reducing body weight than standard care in daily calorie restriction in adults with Type 1 diabetes who are overweight or obese.

Six-month trial 

The US study published in Diabetes Care recruited people with Type 1 diabetes who are also classified as obese by the Centers for Disease Control and Prevention’s body mass index. This makes up about 0.5% of the total US population, notes Varady.

Researchers randomly assigned 32 participants from around Chicago to one of three behaviors for six months: time-restricted eating (eating only between noon and 8 p.m.) with no calorie counting, maintaining a 25% calorie reduction, or a control group with no change in eating behaviors.

After six months, the time-restricted group had reduced their blood sugar levels compared to the calorie-counting group. On average, participants’ HbA1c blood tests showed a clinically significant decrease of around 0.5%.

Notably, time-restricted eating did not raise the risk for extremely high or low blood sugar levels or diabetic ketoacidosis, which is a life-threatening lack of insulin in the body.

“This is the first step to showing time-restricted eating could be a safe, potentially effective method for people with Type 1 diabetes to manage their blood sugar levels,” Varady says.

“Of course, this is just the first step,” she adds. “Anyone making changes to their eating habits, especially those with diabetes, must work closely with their endocrinologist or healthcare provider to find a solution that works for them.”

In future research, Varady hopes to run larger, multisite studies to demonstrate these results on a more universal scale.

Time-restricted eating benefits

Exploring other potential health advantages linked to timing meals, clinical findings from a separate small-scale pilot study recently suggested that time-restricted diets may cut dementia risk in older women.

The findings presented at the Nutrition 2026 conference highlighted that overweight or obese older women limiting their daily eating window — instead of simply reducing their calorie intake — displayed modest cognitive improvements while participating in a weight loss program.

Another paper published in The BMJ revealed intermittent fasting may outperform conventional calorie-restricted weight loss diets. However, researchers have also cautioned that without changing a person’s caloric intake, the protocol does not lead to measurable improvements in metabolism or cardiovascular health.