Being on the edge of your 50's. You'll see a lot of things you eat now start to turn on you by the time you make it to your 60's. For some the transition happens sooner. For others later. Just be aware of what your body is telling you. For the longest time I thought my indigestion and reflux was a heart condition. I didn't even know I had the reflux. But once it was found and treated I no longer had the imagined heart issues.
As for what you eat while riding? Whatever you want that provides energy and you enjoy eating or drinking during the ride. But don't think that because it's good for you while on the bike that you should base all your diet on that.