I'm glad you understand that doing all your goals at once isn't feasible. People want to stop or start something right away and that usually leads to failure. You have an idea what "healthy" means to you and if you can break it into smaller steps, create challenges each week or each month to set goals and ways to reward yourself then you're golden! Of course you'll slip, you'll fail, and fail a lot. But its extremely important not to give up. Just say you'll do better tomorrow. Also, if you can track your progress, since you like math maybe a chart or graph of some kind to give you an illustration it will be all the more motivation you need. Good luck and I'll check in on your progress from time to time!