I've struggled with managing my weight, and I've struggled with managing the condition of my soul. I really don't find that they are very different.
In order to maintain a healthy weight (at 5'3 I once weighed 165 lbs. and I now weigh 127 lbs.); I have to log-in to my app on my iPhone (myfitnesspal) and track my calories daily. I look at how many calories I've consumed, subtract out the calories I've burned with my workout, and I have to stay around 1500 calories a day to maintain my weight. Some people think, "Why are you trying to lose weight?" I'm not! I'm trying NOT TO GAIN weight. Any and every time I stop tracking my calories; tracking every little thing I put in mouth, I WILL GAIN WEIGHT. I'm sorry, but I cannot afford to buy a new wardrobe every 6 months simply because I have the desire to eat a jar of peanut butter.
Sin is the same way...but for some reason, we don't say to people, "Why do you study your Bible EVERYDAY!!!" "Aren't you born again?" ("Aren't you skinny?" "Why are you tracking your calories?" Sound familiar?) Number one, we typically don't meet people who study their Bible every day. Just like you might not meet someone who tracks their calories every day. But I can tell you that I must read my Bible every day for the very same reason that I must track my calories every day.
IT'S A SLOW FADE...
It really is! You don't just go crashing into sin...life-altering, person-shattering, soul-killing sin! No! Sin creeps up...it's the little step over the line, and then, when nothing happens, you take another step over that line, and then you think, "Hey, lightening didn't strike, I don't feel the flames of Hell at my heels, I'll just go a little further..." That is how sin creeps in...that is how weight creeps back in too.
When I'm not in the Word; listening with a quiet heart to what God wants to tell me, that is when sin creeps silently into my soul. I find myself feeling proud, paranoid, and petrified. Those feelings are what can lead me to doubt the plans God has for me, and to start making plans of my own. It never turns out well. I can honestly say that my plans have NEVER been better than God's.