one bit of advice that made sense and changed my life a bit is cut soda out. You never think about it but instead of a can of soda, have a glass of water. It sounds simple, but instead of 10 cans (I guess 5x175 calories per day is almost ~1,000 calories.
I never really thought about it but I switched to drinking water all day like 10 years ago. I have 10 large cups a day easy. Sure I piss like a race horse but it cleanses your body consistently, makes you feel great and you dont have a crash after midday.
I honestly dont really think about it that much, but right now I'm working at a computer game studio (I usually work in film) and these dudes slam down soda all day long its crazy
I know everyone says it, but exercise is the key. After even a week of exercise you dont want to eat shitty foods. I'm fairly fit, I still eat and go out when I want to, but I try to keep my diet during the week pretty on point. Usually instead of a lunch break I'll hit the gym for 45 minutes, walk to and from work. It becomes pretty much a habit and you dont think about it.
I'm Australian and love to party, so I still drink like a mofo on weekends, but outside of that if you keep your week consistent it works out best. I read in mens health once one guy would work his ass off all week long, and have one day of eating shitty food a week. So thats always a good plan if people ever have that problem, plan to go all out once a week on food

and keep your game tight at the gym during the week.