Research from the University of Illinois recently published in the Journal of Gerontology: Medical Sciences and reported in Medical News Today says postmenopausal women who are dieting should maintain protein intake if they do not want to lose muscle tone as they lose body fat.
Adequate protein intake also helps stave off hunger pangs according to the researchers.
Ellen Evans and her team of researchers set out to determine how body composition relates to physical function and found that many older women who diet had a greater risk of losing muscle, as well as fat.
Mina Mojtahedi, a fellow researcher in the study, says muscle loss can undermine balance, overall strength and how well a woman can do regular tasks like walking upstairs or standing up out of a chair.
To counteract this, the researchers found that a high protein diet can reduce muscle loss when the woman is trying to lose fat.
Mojtahedi wrote in her findings that older women who had higher protein intake in their diets lose 3.9% more weight and have a relative gain of 5.8% more thigh muscle than other dieting women of the same age.
The study, which was double-blind for six months, consisted of 31 healthy, postmenopausal women who were considered obese. Each participant followed a 1,400 calorie weight-loss diet based on the USDA’s MyPyramid. Participants were split into 2 groups – one being given powdered whey supplements twice a day and the other being given a placebo containing carbohydrates.
“We believe it’s important to eat protein in the morning and through the day so those amino acids are always available,” says Mojtahedi.
The study involved a pre-and post-evaluation of the women’s strength and balance. Each participant was assessed on their ability to walk 50 feet, raise themselves out of a chair 5 times and lift a book 12 inches above their shoulders.
Also, an MRI (Magnetic Resonance Imaging) measuring muscle volume of the right thigh, amount of fat around the thigh and amount of fat within the thigh muscle was measured both at the beginning and end of the study.
Each group in the study showed that as strength decreased, weight decreased as well. According to Evans, the study also showed that an increase in the amount of muscle relative to fat had positive benefits on balance and performance.
“Even though weight loss in these older women had a negative effect on strength, their reduced weight helped with other aspects of physical function,” comments Evans. “We hypothesize that more vigorous exercise – in particular, resistance training –would preserve even more muscle.”
