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.
I use a lot of spices, fresh veggies and fruit, extra virgin olive oil, nuts, avocado, soybeans and organic ingredients as often as possible. We need fat in our diets and using the healthier fats is key.
All the pre-made sauces in a jar, and frozen and canned vegetables, processed meats, and cheeses which are loaded with artificial ingredients and sodium can get in the way of a healthy diet. My number one advice is to eat fresh, and seasonally.