If you are a postmenopausal dieting woman and you do not want to lose muscle tone as you lose fat, you should keep up your protein intake, researchers from the University of Illinois wrote in the Journal of Gerontology: Medical Sciences. Protein also helps stave off hunger pangs, they add.
Ellen Evans explained that a weight-loss diet which is high in protein protects muscle mass. Evans and team set out to determine how body composition relates to physical function – they had found that many older women who went on a diet tended to have a greater risk of losing muscle, as well as fat.
Fellow researcher, Mina Mojtahedi, said that muscle loss could undermine a woman’s balance, overall strength, and how well she performs everyday tasks, such as walking upstairs or standing up from a chair.
They found that a high protein diet can counteract muscle loss when an older woman is trying to lose fat – thereby protecting her muscle-to-fat ratio.
Mojtahedi wrote that older females who had a higher protein intake during their diets managed to lose 3.9% more weight than other dieting women of the same age, and had a relative gain of 5.8% more thigh muscle volume.
The six-month double-blind study consisted of 31 healthy, postmenopausal obese women who followed a weight loss diet of 1,400-calories based on USDA’s My Pyramid. The participants were split into two groups, one of which received a powdered whey supplement in the morning and again in the afternoon or evening while the other group received 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. Unfortunately, American women tend not to eat much protein, especially when they’re trying to cut calories. But it’s easy to add protein powder into a smoothie or eat a high-protein snack and incorporate a healthier diet into a busy lifestyle.”
Both study groups were encouraged to do light exercise like walking and stretching, and given diet education that included examples of healthy daily menus and a scale to measure portion size.
The study involved a pre-and post evaluation of the participants’ strength and balance, by assessing their ability to walk 50 feet, raising themselves from a chair five times and lifting a book 12 inches above their shoulders.
The muscle volume of the right thigh, the amount of fat around the thigh and the amount of fat within the thigh muscle was measured with MRI (Magnetic resonance imaging) at the beginning and at the end of the study.
Both groups showed that as strength decreased the weight also decreased. Evans noted however, that the study indicates that an increase in the amount of muscle relative to fat had beneficial effects on balance and performance. She said:
“Even though weight loss in these older women had a negative effect on strength, their reduced weight helped with other aspects of physical function. We hypothesize that more vigorous exercise – in particular, resistance training – would preserve even more muscle.”
Written by Petra Rattue