Part of eating better is like the C25K program. You're not going to be able to go from pizza, burgers, soda and beer to salads, fruits, veggies and water in one day. It's a process. When I started the C25K program, one of the things I knew I needed was to drink more water, so I tried to cut back on soda and coffee (which was about 3-4 cups every morning). Gradually backing off, I'm down to coffee about once a week (a cup or two). Eating is the same way. Don't try to go cold turkey, do it gradually. And if you make a mistake, don't beat yourself up for eating too much, or the wrong thing. Learn from it and move on. Get better the next day.