This research was published in the journal Applied Physiology, Nutrition, and Metabolism.

Thirty-five middle-aged men (~59 years old) participated in a study that found that eating a 6-ounce serving of 85% lean ground beef resulted in significant improvements in the rate of muscle protein synthesis following exercise. The investigators measured muscle protein synthesis (MPS), which is essential to the body's ongoing growth, repair and maintenance of skeletal muscle in men who did and did not lift weights. What researchers determined was that the quantity of beef needed for optimal MPS for this age group is double the current recommended serving size of meat.

"Canada's Food Guide now suggests that consuming about 3oz (0.80 g/kg/d) of meat per serving is adequate to provide protein at the recommended level," says Dr. Stuart Phillips, the study's senior author and a researcher with the Exercise Metabolism Research Group at McMaster University. "However, our work shows that the quantity of beef needed to maximize the renewal of new muscle proteins was at least 6oz in middle-aged men. Our findings have clear ramifications for the current recommendations regarding protein to prevent muscle loss in aging."