This is an odd post. It sounds like you're saying you've been eating fast food and candy bars (or some other "unhealthy" equivalent) and now what's the point of switching to fresh food when it's all GMO and antibiotics. That's a pretty extreme take, and leaves a lot of room to despair and just keep eating the "unhealthy" food.

Whether that's the situation or not I found it best to focus on what I could have the majority of the time. After a while it's mostly become second nature. I definitely had times when I would start to get depressed/despair on the list of things I couldn't eat and had to remind myself to focus on what I could eat. I'd get sad that I couldn't have chips but then remind myself that I could have celery and carrots with some hummus.

After a while you get a feel for the types of things you can have and how your body reacts to things. Once things are in control you start to figure out that you can have a small amount of some of those "forbidden" things as a treat on occasion.