But have a protein shake before you start cardio . If you ' re doing LIGHT cardio in the morning , fasted , it ' ll be enough . You ' ll have some glycogen to spare and you probably have enough for 30 minutes . A protein shake might be a bit too heavy , I go straight to 8 gr of 211 bcaas these days . If you ' re talking about cardio AFTER lifting , the protein shake won ' t be enough . You ' ll have depleted your glycogen lifting , so you ' ll need to get it back . The good idea will be coupling that protein shake or straight bcaas with some fast absorption sugar , with consequential high glycemic index . Since I ' m working towards cutting , I simply don ' t do cardio after lifting because the insulin peak impairs fat burning . But if you ' re bulking , that same peak will accelerate the transportation of proteins , glutamine and bcaas to your muscles I really dig BCAAs , can you see ? lol .