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Doubling protein intake while exercising key to strong muscles

New ACU research, published in Sports Medicine, showed eating twice the recommended daily intake of protein built stronger muscles when combined with resistance and endurance training.

Study lead Donny Camera, from the Mary MacKillop Institute for Health Research, said the results could change the way we treat older people at high risk of muscle loss as they age – and may prevent deterioration.

“Current evidence indicates that the recommended intake for protein is not adequate for muscle growth when combined with exercise,” Dr Camera said.

"We are the first to show that combining cardio and strength training exercise with a high protein diet is essential for muscle growth and strength."

“Doubling protein intake and ensuring it is consumed evenly throughout the day –  especially in the morning when protein consumption is usually at its lowest – plays a crucial role in providing the building blocks needed to promote and maintain strong muscles.”

Muscle loss, known as sarcopenia, affects one in three Australians over the age of 60. The condition has higher risk of fractures and falls, and is associated with diabetes, obesity, chronic kidney failure, heart failure and vitamin D deficiency.

Loss of muscle mass as we age is normal. People aged 30 and over will usually lose one to two per cent every year. Some lose much more, affecting their function and quality of life.

The exercise-training study looked at the performance of three groups of men aged between 18 and 30, but Dr Camera said the results were significant for all age groups – from teenagers to 80-year-olds.

“Strong muscles allow us to live actively, independently and reduce our chance of falls,” he said. “These findings have implications for many older adults at high risk of losing muscle mass as we now know that small tweaks can make a big difference and that it is never too late to get started.”

Study participants followed a protein diet more than twice the recommended dietary intake over a 12-week period. During that time, they performed either strength training three days per week or combined strength and cardio training for a total of six days per week.

Protein acts synergistically with exercise to increase muscle mass. Dr Camera said adding protein foods naturally rich in the amino acid leucine — milk, cheese, beef, tuna, chicken, peanuts, soybeans and eggs — was most effective.

Dr Camera said the findings were also relevant for elite athletes as well as those involved in team sports who needed to develop strength, power and endurance.