Congrats on Day 3. I'm on Day 4 myself but I'm doing a short fast. It's great that you want to be a good person although your life has been hard and oh-so-doable. I had a tough time growing up but it hardly feels like it now. Those experiences made me very determined and also pointed me down the path of who I want to be and I'm very grateful for that gift. Hard times are when you can grow the most!
As for "fast foods", fast foods while on the run can be stopping in a grocery store quickly for fruit or a bag-o-precut veggies and hummus. I start to look at grocery stores as my quick pickup when I'm eating on the run. Hunh, I wouldn't have thought of that a few years ago! :)