Weight Loss Part of Week 1

I've decided I need to get in the habit of being more healthy. I was successful in losing a little over 50 lbs. However, I had two foot surgeries and my weight loss declined. I now need part of that 50 lbs again and more. I can't change everything once. I'm challenging myself each week to give something up or add something to my diet/excerise routine. I'm still in my walking boot and with doctor's orders unable to do much at all. Therefore, I need to work on my diet first. I was able to give up soda for over a year and picked up the bad habit about a month and half ago. I haven't had a drink of soda since Tuesday, so today would be working on day 5! Pretty soon need to decide what to challenge myself with for week 2!! Any suggestions??