Fish is very rich with omega-3 fatty acids. Right after working out your body starts feverishly breaking down all of the protein that it can find, including your muscle mass. While you are going home, before you have a chance to eat and digest your steak, this entire time your body will systematically eat itself. Omega-3 stops this process, slowing it down until the right proteins arrive in your stomach. Even if you ate a sandwich with mackerel for breakfast, a while before working out, everything will be alright. One fish contains 74 mg of Vitamin C, almost the daily recommended dose. This vitamin is one of the most important components needed by muscles and tendons for a healthy and happy life.