You can work hard in the gym but if you eat crap, you will not progress. Period.
All performance and body composition goals, and the rate at which you achieve them are determined to a large degree by what you eat. Different goals require different types of caloric intake both in volume and macronutrient breakdown. So body builders will eat differently from marathoners and MMA fighters will eat differently from Olympic weightlifters. Changing one’s diet can be perceived as a personal invasion like few others in the fitness process. But don’t fool yourself, the hours you spend training in the gym will be less effective if you don’t take some time sure to figure out what type of diet will best serve your goals. To quote a kid’s show from my youth, “One of these things is not like the other…”
When it comes to making decisions that affect your long term goals. Choose wisely!