Good core excercises are a great protection against back injuries. It is also a great way to recover from them fully. Don't give up doing what you love if your back starts to hurt.
I broke my back in a real 'agony of defeat' moment rollerblading six years ago. I had an L5 fracture but the biggest problem was the grade four herniation at L5-S1. I had two back surgeries. At the worst, I couldn't walk without limping because I had lost a lot of strength and sensation in my right leg. Then I put my stubborn determination to good use. I set out to recover by doing lots of core excercises starting slow and then building on it. I mountain biked to get strength and coordination back. I had trained for marathons before, nothing was as hard as this. Sometimes it really hurt. Now, I don't hurt at all and the only residual I have is a bit of numbness in my right leg. I can do anything I want to without pain. Now that I feel strong I maintain with 100 crunchs a day (down from 200), mountain biking 3-5 times a week and upper body strength training every other day.

The suggestions I have read about eat less / move more are right on. An irritating side effect (now at my desired weight) is that my metabolism is really high. I can barely stand a sheet on me at night because I get too hot. I lose weight easily if I don't eat enough calories. At 5"7" I try to stay around 130.

I know that if I let myself get soft my risk for reinjury is great. I remember what that felt like and have no intention to let it happen again. Pain is a good motivator.

Never give up.