I will be 58 in August. I know exactly how you feel. I did a little research and the following things have helped me:
1) I searched the web for foods that gives energy ... for example, look at a long distance biker or runner... what do they eat? How can I modify it to my needs? I eat one piece of whole wheat toast w/ peanut butter & honey, a fruit & coffee for breakfast. This has worked great for me. No more waiting until I'm starved.
2) I learned that blueberries, cherries, almonds, hazelnuts, avocados, olive oil, oatmeal, brown rice and whole wheat bread & pasta are consider "belly-fat busters."
3) I gave up soda, limit my fast food to maybe once a week, and eat as little sugar as possible. Fruit has satisfied my sweet tooth.
4) I drink more water. Dehydration can cause fatigue.
5) I set an 11 pm bedtime for myself. I have sleep apnea, so this one is important. How much sleep do you get? Is it good quality sleep?
These are just a few ideas. Talk good to yourself. Never give up!