@kylee07drg – I suppose the best thing to do would be reduce your levels of stress, though I know that isn't always easy. If you can control your environment, then you can take steps to reduce your cortisol levels.
I used to work at a very stressful job, but before I started it, I had been a really laid back person. About three months into my job, I started putting on weight and feeling the effects of stress.
I left that job years later for a much more relaxing one, and now, I'm on a natural low. It feels great not to be rushed and pressured. I think it's safe to say that my cortisol levels have dropped significantly.