Hello there, i wanted to reach out because i am starting a new diet. can protein shakes be a meal substitute? diet and exercise

No. Or maybe yes.: Life is about balance. People need balanced nutrition. If a protein shake is mostly protein or all protein, and we are supposed to have balanced meals, then NO, a protein shake would not appropriately substitute for a balanced meal. However, if the purpose of a protein shake is to eat protein and not the rest of a balanced meal, then it might be fine to do. Details matter. We have no details here.