New study points to time restricted diet as a boon for T2D

Given that more than half a billion people are living with diabetes worldwide, a new study published in The Journal of the American Medical Association (JAMA) Network Open last Friday provides valuable insight into managing the condition. People with type 2 diabetes (T2D), who followed a time-restricted diet lost belly fat and improved their blood sugar as much as those who counted calories, according to a randomised clinical trial that followed a group of 75 people for six months. “Our findings show time restricted eating is a viable alternative for people with type 2 diabetes who are sick of calorie counting for weight loss,” said lead study author Krista Varady, a professor of nutrition at the University of Illinois Chicago.
Diabetes is a chronic, metabolic disease characterised by elevated levels of blood glucose (or blood sugar), which leads over time to serious damage to the heart, blood vessels, eyes, kidneys and nerves. The most common is T2D, usually in adults, which occurs when the body becomes resistant to insulin or doesn’t make enough insulin. In the past 3 decades the prevalence of T2D has risen dramatically in countries of all income levels. Type 1 diabetes, once known as juvenile diabetes or insulin-dependent diabetes, is a chronic condition in which the pancreas produces little or no insulin by itself.
The number of people living with diabetes is projected to more than double to 1.3bn people in the next 30 years, with every country seeing an increase, as published in The Lancet in June this year. The latest and most comprehensive calculations show the current global prevalence rate is 6.1%, making diabetes one of the top 10 leading causes of death and disability. At the super-region level, the highest rate is 9.3% in North Africa and the Middle East, and that number is projected to jump to 16.8% by 2050. The rate in Latin America and the Caribbean is projected to increase to 11.3%. As much as 96% of global cases are T2D. High body mass index was the primary risk for T2D – accounting for 52.2% of T2D disability and mortality – followed by dietary risks, environmental/occupational risks, tobacco use, low physical activity, and alcohol use.
The JAMA Network Open study explored the question if time-restricted eating (TRE) without calorie counting more effective for weight loss and lowering of haemoglobin A1c (HbA1c) levels compared with daily calorie restriction (CR) in adults with T2D. The participants were randomised to one of three groups: 8-hour TRE (eating 12noon to 8pm only, without calorie counting), CR (25% energy restriction daily), or control. There was a 3.6% reduction in weight for time-restricted eating and a 1.8% loss from counting calories compared with those in the control group who were not assigned to a diet. However, changes in HbA1c levels did not differ between the TRE (−0.91%) and CR (−0.94%) groups compared with controls. These findings suggest that time-restricted eating may be an effective alternative strategy to CR for lowering body weight and HbA1c levels in T2D.
“We found that just by limiting the eating window to 8 hours per day, the time restricted eating group naturally cut out about 300 calories per day,” Varady said, even though they were allowed to eat whatever they wanted. Calorie counters were asked to cut 500 calories per day and found tracking the food “too tedious, so they only ended up cutting out 200 calories per day,” Varady said, a factor she attributes to the difference in weight loss. These findings will need to be confirmed by larger randomised control trials with longer follow-up, the authors have recommended.
Qatar faces a significant burden of diabetes, with a projected increase in prevalence from 17.8% (37,179 persons) in 2023 to 29.5% (84,516 persons) by 2050 among adult Qataris aged 20-79 years, according to a paper published in June this year by Laith Abu-Raddad, PhD, Professor of Population Health Sciences at Weill Cornell Medicine-Qatar. Obesity is the main driver of the diabetes epidemic in Qatar, accounting for 57.5% of diabetes cases, it was pointed out in the paper.