Researchers from the University of Adelaide and the South Australian Health and Medical Research Institute (SAHMRI) assessed the effects of time-restricted eating (TRE) in 15 men for one week, The Lead portal reports.
The men, aged 30-70 years and with an average BMI of 33.9 wore a continuous glucose monitor for seven days. All continued to eat their normal diets but some ate only between 8am and 5pm while others ate from noon to 9pm, resulting in a 15-hour fast. Blood glucose response to a standard meal was assessed each day of the study.
The investigators found that TRE improved glucose control, regardless of when the men chose to stop eating. “Our results suggest that modulating when, rather than what, we eat can improve glucose control,” said lead author Associate Professor Leonie Heilbronn from the University of Adelaide Medical School and SAHMRI. “They ate their normal diet during this time, in fact, we told them to keep eating all the foods they usually eat. We did see a tiny amount of weight loss in this study, which may have contributed to the results.”
Intermittent fasting diets such as 16:8 have become popular in recent years but few studies have explored their metabolic effects and impact on glucose levels and insulin profiles in humans.
The study concluded it demonstrated that a week of TRE improved glucose responses to a meal in men at risk for type 2 diabetes, irrespective of when TRF was commenced. However, it conceded that the trial should be repeated in larger cohorts with more tightly controlled free‐living periods to confirm the result. Associate Professor Heilbronn said that while the early result showed promise for controlling blood glucose, a larger study over a longer duration was required to fully investigate the effectiveness. “Time-restricted eating regimes demonstrate that we can enjoy foods that are perceived to be ‘bad’ for us, if we eat them at the right time of day, when our bodies are more biologically able to deal with the nutrient load,” she said. “And perhaps more importantly, if we allow our bodies to have more time fasting each night.”
Fred Rochler, who has been participating in a follow-up study, has undertaken a TRE regime in which he ate his normal diet only from 9.30am to 7.30pm over a similar eight-week trial. “Over the trial, I found that my fasting blood glucose tolerance improved significantly,” he said. “It changed from ‘increased risk’ level to ‘normal’. This was without changing any of the foods that I like to eat.”