The benefit of time-restricted eating

Dr Evelyn Parr from the Mary Mackillop Institute for Health Research reveals how a new study into time restricted eating could be a gamechanger for those with type 2 diabetes, and the perils of late night snacking for everyone.

Dr Parr has always been interested in diet and exercise, “but I’m not really someone who worries about the top one per cent gains for athletes,” she said. “I’d much rather contribute to a larger pool. I want to work with people that are trying to find healthy ways of living and understand how diet and exercise have an effect.”

Good timing

Dr Parr’s latest research questions whether time-restricted eating could be an option for curbing the diabetes epidemic, and possibly help us all live healthier lives. This is particularly good news for the more than one million Australians who have type 2 diabetes. 

The research Dr Parr conducted found that eating all meals and snacks within a nine-hour window, and fasting for the rest of the time, was a good way to limit post-dinner snacking. For many of us with busy lifestyles, our tendency to start eating early and not stop until just before bed is a pattern playing havoc with our health.

“The best way to describe it is we all have an internal body clock that tells us when it’s time to sleep, when to wake up, and we have different hormones working at different times,” she explained. “And with so many of us having easy access to food literally 24 hours a day with no restrictions, it encourages us to lengthen our eating time through the day and night. But this includes the times when our bodies are not really prepared or naturally ready to eat.

“So, if someone eats until 10pm or later and then has breakfast at 7am, they don’t have a long overnight fasting period,” she said. “The length of that period seems to be important in improving and regulating metabolism.

“The end of the day is when our body responds poorly to insulin – the hormone released from the pancreas in response to food. When we eat late, insulin doesn’t work as well, so we get exacerbated glucose responses to that food. It’s also when we eat our biggest meals and consume sugary snacks and alcohol.

“This means time restricted eating is about aligning your eating with your body’s preparedness for it and only eating at optimal times. It offers a guide and timeframe to follow, rather than dictating specific foods you shouldn’t eat, and it can help minimise overeating.”

Fasting feasibility

Dr Parr said people with type 2 diabetes may be able to benefit from time restricted eating as a long-term dietary strategy for blood glucose management, and extended fasting has been shown to improve metabolic health outcomes even without substantial weight loss.

“We found that time restricted eating was feasible for five days of the week with no adverse effects,” she said.

“This first study was important as a diet may work well in the lab setting, but if it can’t be adhered to in the real world then it’s not practical or useful.

Dr Parr said this approach gives the body a long break from food each night and reinforces our natural circadian rhythms.

“Type 2 diabetes can be a really difficult disease to manage” she said. “Now that we know this is a strategy that people with diabetes can adhere to, our next step is to investigate how longer term time restricted eating might better manage or even improve blood sugar levels in people with type 2 diabetes.”

Learn more about where higher degree research at ACU could lead, and contact the Mary MacKillop Institute for Health Research for more information about Dr Parr’s research projects.