You are the master of your environment. You've got your own head, your own mind. So once you figure out what you want for yourself, you have to create the proper environment to make sure you can live out all the things you want.
I believe in eating smaller meals more often throughout the day to keep the metabolism going. Don't deprive yourself, just make better choices. At 50 years old it is definitely a lot harder to stay in shape then it was when I was in my 20's.

