A simple change in when people eat may help some adults with type 1 diabetes improve their blood sugar, according to an early clinical study from the University of Illinois Chicago.
Researchers found that limiting eating to an eight-hour period each day appeared safe in the small group studied and produced better blood sugar results than calorie restriction.
Type 1 diabetes is an autoimmune disease in which the body’s immune system destroys cells in the pancreas that make insulin. Insulin is essential because it helps glucose, or sugar, move from the blood into cells where it can be used for energy.
People with type 1 diabetes therefore need insulin every day to survive. They must carefully balance insulin doses with food, exercise and other factors because both very high and very low blood sugar can be dangerous.
Weight management can add another challenge. Some people with type 1 diabetes also live with obesity, which can make the body less responsive to insulin and may increase the risk of heart and blood vessel disease.
Researchers led by University of Illinois Chicago professor Krista Varady wanted to know whether time-restricted eating could help this group. Varady has studied intermittent fasting for many years, but there has been little research on this approach in people with type 1 diabetes because of concerns about blood sugar safety.
Time-restricted eating focuses on the clock rather than counting every calorie. People eat during a set period each day and avoid calorie-containing food and drinks outside that window.
The study recruited 32 adults from the Chicago area who had type 1 diabetes and obesity according to body mass index. The participants were randomly placed into one of three groups and followed for six months.
One group could eat only between noon and 8 p.m. each day but did not have to count calories. A second group was asked to reduce daily calorie intake by 25%, while a third group continued its usual habits.
The researchers measured changes in blood sugar control using HbA1c. This common blood test gives an estimate of a person’s average blood glucose over roughly the previous two to three months.
After six months, the time-restricted eating group had better blood sugar results than the calorie-restriction group. Their HbA1c fell by an average of about 0.5 percentage points.
A change of half a percentage point can be meaningful in diabetes care, although its importance depends on a person’s starting HbA1c and overall health. The study was not large enough to determine whether the improvement would reduce long-term complications such as kidney, eye, nerve or heart disease.
Safety was especially important because fasting can create risks for people who depend on insulin. If insulin, food and activity are not properly balanced, blood sugar can fall too low, while too little insulin can cause dangerously high blood sugar.
One particularly serious complication is diabetic ketoacidosis, or DKA. It occurs when the body does not have enough insulin and begins producing high levels of acidic substances called ketones, which can become life-threatening without urgent treatment.
In this study, time-restricted eating did not increase episodes of dangerously high or low blood sugar or diabetic ketoacidosis. That result is encouraging because safety has been one of the biggest concerns about testing fasting approaches in type 1 diabetes.
Varady described the research as a first step rather than proof that everyone with type 1 diabetes should begin fasting. She stressed that people with diabetes should work with an endocrinologist or another healthcare professional before making major changes to meal timing.
That warning matters because changing when food is eaten can also change how much insulin is needed and when it should be given. An eating schedule that is safe for one person may not be appropriate for another.
The study was published in Diabetes Care, a peer-reviewed journal of the American Diabetes Association. The research team included experts from the University of Illinois Chicago in nutrition, diabetes and related health fields.
The study has several strengths. Participants were randomly assigned to different approaches, the experiment lasted six months rather than only a few days, and researchers directly compared time-restricted eating with a traditional calorie-reduction strategy.
However, 32 participants is a very small sample. A study of this size can identify promising signals, but it cannot establish how well the approach would work across the much larger and more diverse population of people with type 1 diabetes.
The participants also had obesity, so the findings should not automatically be applied to people with type 1 diabetes who have a lower body weight. Researchers will need to examine different ages, insulin treatments, lifestyles and health conditions.
Another unanswered question is whether people can comfortably follow a noon-to-8 p.m. eating window for years. Long-term success depends not only on blood tests but also on hunger, social routines, quality of life and whether the eating pattern can be maintained.
Overall, the results are encouraging because they suggest time-restricted eating may offer a simpler alternative to constant calorie counting for some adults with type 1 diabetes and obesity.
Larger studies at several medical centers are now needed to confirm both the benefits and the safety before the approach can become a standard part of diabetes care.
Source: University of Illinois Chicago.
