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Muscle growth not impaired by time-restricted eating, research

 Time restricted eating (TRE) has become a popular dietary trend for those wanting to hack their health – whether it is to lose weight or reduce the risk for obesity, diabetes, and cardiovascular disease but does it affect muscle health?

In a world-first, proof of concept study, published in a special issue of the journal Obesity dedicated to investigations of TRE, Australian Catholic University (ACU) researchers found reducing the daily ‘eating window’ from 12 to eight hours a day did not impair rates of muscle growth.

Lead researcher Dr Evelyn Parr, from the Mary MacKillop Institute for Health Research, said the new research was an important step towards understanding how time-restricted eating affected muscle function and growth.

“We need regular intake of dietary protein to help maintain healthy muscle tissue, but because time-restricted eating limits the time window of eating we wondered if it had a “down” side which might impair muscle growth,” Dr Parr said.

“From a TRE perspective, we didn’t know whether narrowing the time window over which food (and protein) was consumed was going to impact muscle growth. We measured the rate at which the muscle grows over 10 days during time-restricted eating and found no detrimental effect.

“This is an important finding because everyone wants to know which diet is the best.”

Dr Parr said long-term studies are now needed to determine if TRE-induced weight loss can be achieved without compromising muscle health.

“Most diets cause a loss of lean mass, part of that is water and part is muscle,” she said. “We don’t have a drug or any other way to increase our muscle apart from moving and using it, so if a diet causes us to lose muscle that is not a very good health outcome.”

Age-related muscle loss, known as sarcopenia, affects one in three Australians over the age of 60. Sarcopenia increases the risk of fractures and falls, and is associated with diabetes, obesity, chronic kidney failure, heart failure and vitamin D deficiency.

Loss of muscle mass happens as we age. People after the age of 40 typically lose around one per cent of their muscle mass every year. Dr Parr said it is integral to ensure our behaviours, including dietary interventions which contribute to weight loss, do not exacerbate the loss of muscle mass.

Critically the study, which involved adults with overweight or obesity, found that reducing the daily eating window from 12 to eight hours a day – where breakfast was delayed and dinner was earlier – improved daily blood sugar levels despite the same amount of food being consumed over a 24-hour period.

“TRE can be an effective intervention for glucose management in people with impaired glucose tolerance or type 2 diabetes,” Dr Parr said.

Research has shown TRE can reduce insulin resistance, inflammation, and risk factors for cardiovascular disease, improve brain function and repair DNA.

TRE is widely seen as a practical way to deliver the health and metabolic changes that unsustainable diets cannot.

Want to know more? Listen to Dr Parr’s podcast interview on Super Human Radio.

Media Contact: Elisabeth Tarica, Australian Catholic University on 0418 756 941 or elisabeth.tarica@acu.edu.au