- Time-restricted eating, a type of intermittent fasting, may lower blood sugar and reduce diabetes risk, according to one study.
- Experts say the approach supports healthy insulin function and blood sugar management.
- Dietitians explain the findings and share who could benefit the most.
Most people with high blood sugar or diabetes tend to focus on what they are eating to try and keep their blood sugar levels stable. However, research suggests that when you eat may also play a role. More specifically, one study found that a particular type of intermittent fasting may reduce blood sugar and diabetes risk. Read on to discover what they found, plus who could benefit from the approach.
Meet the experts: Joanne Bruno, M.D., Ph.D., lead study author and an endocrinologist and clinical assistant professor at NYU Grossman School of Medicine; Scott Keatley, R.D., co-owner of Keatley Medical Nutrition Therapy; Pouya Shafipour, M.D., a board-certified family and obesity medicine physician at Saint John’s Physician Partners in Santa Monica, CA; Jessica Cording, R.D., author of The Little Book of Game-Changers; Beth Warren, M.S., R.D.N., author of Secrets of a Kosher Girl.
The study, which was published in the journal iScience, followed 10 people who had obesity and high blood sugar levels. The researchers had participants follow either an early time-restricted feeding pattern, where 80% of their calories were consumed before 1 p.m., or a normal eating pattern, where half the day’s calories were eaten after 4 p.m. (Food was provided for them.) The study participants did one eating pattern for a week and then the other for an additional week. They also wore continuous blood sugar monitors (CGMs) throughout the study.
While the study participants’ weight stayed constant throughout the study, blood sugar levels were more consistent and less elevated when they got the bulk of their daily calories before 1 p.m.
This eating pattern and its impact on blood sugar “may help prevent those with prediabetes or obesity from developing type 2 diabetes,” said lead study author Joanne Bruno, M.D., Ph.D., an endocrinologist and clinical assistant professor at NYU Grossman School of Medicine. Prediabetes is a condition in which blood sugar levels are higher than normal but not high enough to be classified as type 2 diabetes.
It’s important to note that the study didn’t explore why this association exists—it just found a link. Still, there are a few theories.
“Many aspects of our health and within our body fluctuate according to certain circadian patterns,” Dr. Bruno said. Taking in more calories during times of day when you tend to be most active may help synch up your hormonal and metabolic health, she added.
Time-restricted eating may also support healthy blood sugar management. “This approach might help lower the risk of developing type 2 diabetes because prolonged periods of elevated blood sugar can lead to insulin resistance, a key factor in the development of type 2 diabetes,” explained Scott Keatley, R.D., co-owner of Keatley Medical Nutrition Therapy. “By reducing the time that blood sugar is above normal, time-restricted eating could potentially prevent the progression from prediabetes to type 2 diabetes.”
Your pancreas, which makes insulin that helps carry sugar from your blood into your cells, is also more active during the day, explained Pouya Shafipour, M.D., a board-certified family and obesity medicine physician at Saint John’s Physician Partners in Santa Monica, CA. “You have more insulin sensitivity during the day and less at night,” he said. “If you frontload your calories, they will metabolize better and fluctuations will go down significantly.”
Having a larger window of time where you’re not eating as much also “gives your body time for blood sugar levels to come down,” said Jessica Cording, R.D., author of The Little Book of Game-Changers. What’s more, sticking to a window where you eat most of your calories “can help prevent eating habits that contribute to poor food choices and health, such as late-night snacking and eating too many calories in one day,” said Beth Warren, M.S., R.D.N., author of Secrets of a Kosher Girl.
The results of this 2024 study have been replicated by other scientists. For example, a 2025 study in Clinical Nutrition found that people who practiced time-restricted eating for 12 weeks saw significant improvements in glycemic control and fasting blood glucose, plus reductions in body weight and triglycerides, all of which contribute to a lower diabetes risk.
Caution: This approach isn’t for everyone
While time-restricted eating seems to be an effective approach for reducing your risk of developing type 2 diabetes, it may not be the best strategy for everyone. For starters, time-restricted eating and other intermittent fasting protocols are not recommended for people with a history of disordered eating. What’s more, this study specifically looked at people who had obesity and high blood sugar levels—not those who already had type 1 or type 2 diabetes.
Patients who rely on insulin for blood sugar management should be wary of any type of fasting, Keatley added. “Intermittent fasting may not be safe for insulin-dependent diabetics because it can lead to periods of both low and high blood sugar,” he explained. “Insulin-dependent diabetics need to carefully balance their food intake and insulin administration; if food intake becomes too unpredictable, it could lead to dangerous fluctuations in blood sugar levels.”
If you’re not dependent on insulin for blood sugar management but you’re concerned about your diabetes risk, Dr. Bruno said it’s a good idea to consult with your doctor before making any major dietary changes such as adopting a time-restricted eating protocol. They’ll be able to make personalized recommendations to help ensure you’re still getting all the nutrients you need, like protein, fat, and fiber, within the smaller eating window. “All meals should incorporate these nutrients for blood sugar management,” said Cording.
If you believe you are struggling with an eating disorder and need support, call the National Eating Disorders Association helpline at (800) 931-2237. You can text HOME to 741741 to message with a trained crisis counselor from the Crisis Text Line for free.
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