Severe skeletal wasting and catabolic weight loss are highly common among patients with heart failure with reduced ejection fraction (HFrEF). This prospective randomized controlled trial will compare changes in the muscle mass in the arms and the legs (appendicular lean mass) in patients with HFrEF randomized between 3 groups of no, low- or high-dose protein supplementation. The dietary protein supplementation will be Ensure(R) products manufactured by Abbott Nutrition. The Investigators hypothesize that skeletal muscle wasting in HFrEF is promoted by neurohumoral activation of catabolic metabolism (such as GDF-15 and ActRII pathways) and can be at least partially reversed by increased dietary protein intake. It is anticipated that this study will determine whether dietary protein supplementation helps to prevent muscle wasting and will advance understanding of the GDF-15 and ActRII muscle wasting pathways.