Every day, I replace one meal (usually breakfast, because I can make it on the go if I need to) with a smoothie and protein/superfood shake. I have more energy, I feel great at the beginning of the day, which sets off the rest of my day. I have craved less of the crap, and want more and more raw foods such as a salad for lunch. My meals are not perfect, and I will eat on occasion (moderation) a nice cheeseburger and fries. As long as I am not eating that every day, and it is once in awhile, then my body feels fine.
Your body knows when to stop eating the junk - listen to it. Your body knows how much to eat - listen to it. Be smart, you know at least the basics on what is healthy and what is not. Then learn more about what is healthy and what is not in the ingredients in your food. You know when you're going to pay for something you just stuck your mouth, we make mistakes, just remember how you felt last time and don't do it the next time. Choose something healthier. Your body, mind, energy and soul will thank you!