Getting enough protein is important when losing weight to prevent loss of lean muscle mass. (optimisingnutrition.com)
Finally, loss of lean muscle mass slows down your metabolic rate so you burn fewer calories with activity and at rest. (cathe.com)
Protein is required to supply the building blocks for renewal and maintenance of the body's cells, from muscle tissue to organs, skin and coat, so reducing it too much usually quickly results in loss of lean muscle mass, poor skin and coat quality and sluggish behavior. (dogfoodproject.com)